BelongsToMany - resourceClass on null in Nova, works outside of Nova

I have BelongsToMany relationship between two of my Models. Their names are TicketType and EventType.

It looks like this in my Eloquent models:

class TicketType extends Model
{
    /// lots of code

    public function eventTypes(): BelongsToMany
    {
        return $this->belongsToMany(EventType::class, 'ticket_type_event_type');
    }
}

class EventType extends Model
{
    /// lots of code

    public function ticketTypes(): BelongsToMany
    {
        return $this->belongsToMany(TicketType::class, 'ticket_type_event_type');
    }
}

And it looks like this in my Nova Resources:

class TicketType extends Resource
{
    /// bla bla bla...

    public function fields(NovaRequest $request)
    {
        return [
            BelongsToMany::make(__('Event Types'), 'eventTypes', EventType::class),
        ];
    }
}

class EventType extends Resource
{
    /// bla bla bla...

    public function fields(NovaRequest $request)
    {
        return [
            BelongsToMany::make(__('Ticket Types'), 'ticketTypes', TicketType::class),
        ];
    }
}

And then this is from my log:

[2022-06-02 19:32:34] local.ERROR: Attempt to read property "resourceClass" on null {"userId":1,"exception":"[object] (ErrorException(code: 0): Attempt to read property \"resourceClass\" on null at /Users/jimmiejohansson/Code/tickets/vendor/laravel/nova/src/Http/Controllers/AttachableController.php:28)
[stacktrace]
#0 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/HandleExceptions.php(255): Illuminate\Foundation\Bootstrap\HandleExceptions->handleError(2, 'Attempt to read...', '/Users/jimmiejo...', 28)
#1 /Users/jimmiejohansson/Code/tickets/vendor/laravel/nova/src/Http/Controllers/AttachableController.php(28): Illuminate\Foundation\Bootstrap\HandleExceptions->Illuminate\Foundation\Bootstrap\{closure}(2, 'Attempt to read...', '/Users/jimmiejo...', 28)
#2 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Routing/Controller.php(54): Laravel\Nova\Http\Controllers\AttachableController->__invoke(Object(Laravel\Nova\Http\Requests\NovaRequest), 'ticket-types', '77', 'event-types')
#3 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php(45): Illuminate\Routing\Controller->callAction('__invoke', Array)
#4 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Routing/Route.php(261): Illuminate\Routing\ControllerDispatcher->dispatch(Object(Illuminate\Routing\Route), Object(Laravel\Nova\Http\Controllers\AttachableController), '__invoke')
#5 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Routing/Route.php(204): Illuminate\Routing\Route->runController()
#6 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Routing/Router.php(725): Illuminate\Routing\Route->run()
#7 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(141): Illuminate\Routing\Router->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#8 /Users/jimmiejohansson/Code/tickets/vendor/laravel/nova/src/Http/Middleware/Authorize.php(18): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#9 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Laravel\Nova\Http\Middleware\Authorize->handle(Object(Illuminate\Http\Request), Object(Closure))
#10 /Users/jimmiejohansson/Code/tickets/vendor/laravel/nova/src/Http/Middleware/BootTools.php(20): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#11 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Laravel\Nova\Http\Middleware\BootTools->handle(Object(Illuminate\Http\Request), Object(Closure))
#12 /Users/jimmiejohansson/Code/tickets/vendor/laravel/nova/src/Http/Middleware/DispatchServingNovaEvent.php(24): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#13 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Laravel\Nova\Http\Middleware\DispatchServingNovaEvent->handle(Object(Illuminate\Http\Request), Object(Closure))
#14 /Users/jimmiejohansson/Code/tickets/vendor/inertiajs/inertia-laravel/src/Middleware.php(88): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#15 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Inertia\Middleware->handle(Object(Illuminate\Http\Request), Object(Closure))
#16 /Users/jimmiejohansson/Code/tickets/app/Http/Middleware/RecordLastActivity.php(25): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#17 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): App\Http\Middleware\RecordLastActivity->handle(Object(Illuminate\Http\Request), Object(Closure))
#18 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Routing/Middleware/SubstituteBindings.php(50): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#19 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Illuminate\Routing\Middleware\SubstituteBindings->handle(Object(Illuminate\Http\Request), Object(Closure))
#20 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Auth/Middleware/Authenticate.php(44): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#21 /Users/jimmiejohansson/Code/tickets/vendor/laravel/nova/src/Http/Middleware/Authenticate.php(31): Illuminate\Auth\Middleware\Authenticate->handle(Object(Illuminate\Http\Request), Object(Closure))
#22 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Laravel\Nova\Http\Middleware\Authenticate->handle(Object(Illuminate\Http\Request), Object(Closure))
#23 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/VerifyCsrfToken.php(78): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#24 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Illuminate\Foundation\Http\Middleware\VerifyCsrfToken->handle(Object(Illuminate\Http\Request), Object(Closure))
#25 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/View/Middleware/ShareErrorsFromSession.php(49): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#26 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Illuminate\View\Middleware\ShareErrorsFromSession->handle(Object(Illuminate\Http\Request), Object(Closure))
#27 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Session/Middleware/StartSession.php(121): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#28 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Session/Middleware/StartSession.php(64): Illuminate\Session\Middleware\StartSession->handleStatefulRequest(Object(Illuminate\Http\Request), Object(Illuminate\Session\Store), Object(Closure))
#29 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Illuminate\Session\Middleware\StartSession->handle(Object(Illuminate\Http\Request), Object(Closure))
#30 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/AddQueuedCookiesToResponse.php(37): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#31 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse->handle(Object(Illuminate\Http\Request), Object(Closure))
#32 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/EncryptCookies.php(67): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#33 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Illuminate\Cookie\Middleware\EncryptCookies->handle(Object(Illuminate\Http\Request), Object(Closure))
#34 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(116): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#35 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Routing/Router.php(726): Illuminate\Pipeline\Pipeline->then(Object(Closure))
#36 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Routing/Router.php(703): Illuminate\Routing\Router->runRouteWithinStack(Object(Illuminate\Routing\Route), Object(Illuminate\Http\Request))
#37 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Routing/Router.php(667): Illuminate\Routing\Router->runRoute(Object(Illuminate\Http\Request), Object(Illuminate\Routing\Route))
#38 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Routing/Router.php(656): Illuminate\Routing\Router->dispatchToRoute(Object(Illuminate\Http\Request))
#39 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(167): Illuminate\Routing\Router->dispatch(Object(Illuminate\Http\Request))
#40 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(141): Illuminate\Foundation\Http\Kernel->Illuminate\Foundation\Http\{closure}(Object(Illuminate\Http\Request))
#41 /Users/jimmiejohansson/Code/tickets/vendor/livewire/livewire/src/DisableBrowserCache.php(19): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#42 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Livewire\DisableBrowserCache->handle(Object(Illuminate\Http\Request), Object(Closure))
#43 /Users/jimmiejohansson/Code/tickets/vendor/laravel/nova/src/Http/Middleware/ServeNova.php(23): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#44 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Laravel\Nova\Http\Middleware\ServeNova->handle(Object(Illuminate\Http\Request), Object(Closure))
#45 /Users/jimmiejohansson/Code/tickets/vendor/barryvdh/laravel-debugbar/src/Middleware/InjectDebugbar.php(67): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#46 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Barryvdh\Debugbar\Middleware\InjectDebugbar->handle(Object(Illuminate\Http\Request), Object(Closure))
#47 /Users/jimmiejohansson/Code/tickets/vendor/laravel/vapor-core/src/Http/Middleware/ServeStaticAssets.php(21): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#48 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Laravel\Vapor\Http\Middleware\ServeStaticAssets->handle(Object(Illuminate\Http\Request), Object(Closure))
#49 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/TransformsRequest.php(21): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#50 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/ConvertEmptyStringsToNull.php(31): Illuminate\Foundation\Http\Middleware\TransformsRequest->handle(Object(Illuminate\Http\Request), Object(Closure))
#51 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull->handle(Object(Illuminate\Http\Request), Object(Closure))
#52 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/TransformsRequest.php(21): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#53 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/TrimStrings.php(40): Illuminate\Foundation\Http\Middleware\TransformsRequest->handle(Object(Illuminate\Http\Request), Object(Closure))
#54 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Illuminate\Foundation\Http\Middleware\TrimStrings->handle(Object(Illuminate\Http\Request), Object(Closure))
#55 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/ValidatePostSize.php(27): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#56 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Illuminate\Foundation\Http\Middleware\ValidatePostSize->handle(Object(Illuminate\Http\Request), Object(Closure))
#57 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/PreventRequestsDuringMaintenance.php(86): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#58 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Illuminate\Foundation\Http\Middleware\PreventRequestsDuringMaintenance->handle(Object(Illuminate\Http\Request), Object(Closure))
#59 /Users/jimmiejohansson/Code/tickets/vendor/fruitcake/laravel-cors/src/HandleCors.php(38): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#60 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Fruitcake\Cors\HandleCors->handle(Object(Illuminate\Http\Request), Object(Closure))
#61 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Http/Middleware/TrustProxies.php(39): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#62 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(180): Illuminate\Http\Middleware\TrustProxies->handle(Object(Illuminate\Http\Request), Object(Closure))
#63 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(116): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#64 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(142): Illuminate\Pipeline\Pipeline->then(Object(Closure))
#65 /Users/jimmiejohansson/Code/tickets/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(111): Illuminate\Foundation\Http\Kernel->sendRequestThroughRouter(Object(Illuminate\Http\Request))
#66 /Users/jimmiejohansson/Code/tickets/public/index.php(52): Illuminate\Foundation\Http\Kernel->handle(Object(Illuminate\Http\Request))
#67 /Users/jimmiejohansson/.composer/vendor/laravel/valet/server.php(234): require('/Users/jimmiejo...')
#68 {main}
"} 

And in Nova, this is the Url I am accessing:

https://tickets.test/nova/resources/ticket-types/77/attach/event-types?viaRelationship=eventTypes&polymorphic=0

Then when loading the error message is:

Attempting to read property "resourceClass"  on null.

However, when I am using tinker, everything works when loading the relationships. For example I can access all the eventTypes of a TicketType there. It seems like there are something inside Nova that is screwing up(?).

Please, what is going on?