为什么$ nextRegistration-> participant-> contains包含显示错误？

I have this code to show the next registrations of a user in a conference:

$nextRegistrations = $user->registrations()
          ->with('participants.registration_type')
          ->whereHas(
              'conference',
              function ($query) {
                  $query->where('end_date', '>', now());
              }
          )->paginate($pageLimit);

Then, in the view I want to show for each registration a link "Get certificate" if the column "available_certificate" of the "registration_types" table has the value "Y". But its not working with "@if ($nextRegistration->participants->contains('certificate_available', 'Y'))". Do you know why? The the " {{dump($nextRegistration->participants->contains('certificate_available', 'Y'))}}" shows "false" for the 3 list items (3 registrations).

<ul class="list-group">
    @foreach($nextRegistrations as $nextRegistration)
        @foreach($nextRegistration->participants as $participant)
            @if(!empty($nextRegistration->conference) || !empty($nextRegistration->conference->start_date))
                    @if ($nextRegistration->participants->contains('certificate_available', 'Y'))                                                 
                    <a href="{{route('conferences.certificateInfo',
                    [
                    'regID'=> $nextRegistration->id])}}"
                           class="btn btn-primary ml-2">Download certificate</a>
                    @endif
                </li>
            @endif
        @endforeach
    @endforeach

    </ul>

Db structure:

conferences table:

id  name
1   conference test 1

registrations table:

id    conference_id        user_that_did_registration
1           1                            2
2           1                             2
3            1                             2

participants table:

id      registration_id      registration_type_id          name      
1               1                   1                       Jake       
2               2                   1                       John
3               3                   1                       Paul
4               3                   2                       Peter

registration_types table:

id     name       conference_id     certificate_id      certificate_available
1      r1               1                1                        Y 
2      r2               1                 2                      Y

certificate table:

id    content
1     <p>cert 1</p>
2     <p>cert 2</p>

I think you need to filter and then check the count, see our comments above:

$results = $nextRegistration->participants->filter(function ($participant) {
    return $participant->registration_type->contains('certificate_available', 'Y');
});

if (count($results) > 0) {
    // Do something
}