Empty validation errors bag on Vapor production server only

My Laravel 6.2 application is working as expected on my local environment but I have a strange issue on my production environment deployed with Laravel Vapor:

After submitting a form with invalid data, the user is redirected back to the form however the validation errors are not displayed...

I suspected an issue with the session configuration and tried both the 'file' and 'database' driver but nothing changed. The Laravel Vapor documentation doesn't mention the session driver therefore any configuration should work.

I also tried debugging the session with Telescope but the session data transiting looked exactly the same as my local environment.

I'm not sure were else to look at this stage, it doesn't seem to be a common issue. Any ideas ?

Edit: I answered myself here: https://laracasts.com/discuss/channels/laravel/whats-wrong-with-my-middleware