Repeater with MorphTo relationship don't work on create page

Group::make()
  ->relationship('entity')
  ->schema([
    Repeater::make('questions')
      ->relationship()
      ->schema([
        Textarea::make('question'),
        Repeater::make('options')
          ->relationship()
          ->schema([
            TextInput::make('option'),
          ]),
    ]),
]),

Call to undefined method App\Models\Content::questions()