Order of where conditions in (eloquent) query

I made some sort of logbook for my organization. The admin creates Tags and gives authority to the users to create and read logbook messages with those specific tags. So far so good.

There is also a button 'show new messages since my last login'. Works fine, but there is a bug. When a user presses that button, he does get a list of logbook messages that were created since he last logged in, but the messages are not restricted to the ones he is authorized to read. He also sees messages with other tags than the once assigned to his account.

This is my (simplified, since there are some other filter possibilities) query:

$logitemsq = Logmelding::when($this->lastlogin, function($query){
            $query->where('created_at','>=',$this->lastlogin->created_at)
            ->where('datum','<=',Carbon::now()->format('Y-m-d'))
            ->orWhereHas('reacties', function($q){
                $q->where('created_at','>=',$this->lastlogin->created_at)
                ->where('datum','<=',Carbon::now()->format('Y-m-d'))
                ;
            })
            ;
        }) 
->where(function ($query) use ($tagsvanuser, $gebruikersvanuser, $afdelingenvanuser){

             $query->whereHas('tags', function($q) use ($tagsvanuser){
                $q->whereIn('tag_id',$tagsvanuser);
            })
            ->where(function($q) use ($gebruikersvanuser, $afdelingenvanuser){
                $q->doesntHave('gebruikers')
                ->orWhereHas('gebruikers', function($q) use ($gebruikersvanuser, $afdelingenvanuser){
                    $q->whereIn('gebruiker_id',$gebruikersvanuser)
                    ->orWhereHas('afdelingen', function($q) use ($afdelingenvanuser){
                        $q->whereIn('afdeling_id',$afdelingenvanuser);
                    })
                    ;
                })
                
                ;
            })
            ->orWhere('user_id',Auth::user()->id)
            ->orWhereHas('getagdecollegas', function ($q) {
                $q->where('user_id', Auth::user()->id);
            })
            ;
        })

When I change the order of the 2 elements in my query, the bug is gone. I don't understand why that is...