I'm getting this error on the results page of a quiz. I haven't been able to identify specifically what's going wrong, but the issue appears to be $paragraph->getRevisionId() 33 of MatchingResponse.php
Notice: Undefined offset: 651 in Drupal\quiz_matching\Plugin\quiz\QuizQuestion\MatchingResponse->score() (line 33 of modules/contrib/quiz/question_types/quiz_matching/src/Plugin/quiz/QuizQuestion/MatchingResponse.php).
Drupal\quiz_matching\Plugin\quiz\QuizQuestion\MatchingResponse->score(Array) (Line: 231)
Drupal\quiz\Form\QuizQuestionAnsweringForm->submitForm(Array, Object)
call_user_func_array(Array, Array) (Line: 114)
Drupal\Core\Form\FormSubmitter->executeSubmitHandlers(Array, Object) (Line: 52)
Drupal\Core\Form\FormSubmitter->doSubmitForm(Array, Object) (Line: 593)
Drupal\Core\Form\FormBuilder->processForm('quiz_question_answering_form', Array, Object) (Line: 144)
Drupal\autosave_form\Form\AutosaveFormBuilder->processForm('quiz_question_answering_form', Array, Object) (Line: 321)
Drupal\Core\Form\FormBuilder->buildForm('Drupal\quiz\Form\QuizQuestionAnsweringForm', Object) (Line: 97)
Drupal\autosave_form\Form\AutosaveFormBuilder->buildForm('Drupal\quiz\Form\QuizQuestionAnsweringForm', Object) (Line: 219)
Drupal\Core\Form\FormBuilder->getForm('Drupal\quiz\Form\QuizQuestionAnsweringForm', Object, Object) (Line: 201)
Drupal\quiz\Controller\QuizQuestionController->take(Object, '10')
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 573)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 124)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 151)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 68)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 52)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 708)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)
Warning: array_flip(): Can only flip STRING and INTEGER values! in Drupal\Core\Entity\ContentEntityStorageBase->loadMultipleRevisions() (line 584 of core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php).
Drupal\Core\Entity\ContentEntityStorageBase->loadMultipleRevisions(Array) (Line: 551)
Drupal\Core\Entity\ContentEntityStorageBase->loadRevision(NULL) (Line: 33)
Drupal\quiz_matching\Plugin\quiz\QuizQuestion\MatchingResponse->score(Array) (Line: 231)
Drupal\quiz\Form\QuizQuestionAnsweringForm->submitForm(Array, Object)
call_user_func_array(Array, Array) (Line: 114)
Drupal\Core\Form\FormSubmitter->executeSubmitHandlers(Array, Object) (Line: 52)
Drupal\Core\Form\FormSubmitter->doSubmitForm(Array, Object) (Line: 593)
Drupal\Core\Form\FormBuilder->processForm('quiz_question_answering_form', Array, Object) (Line: 144)
Drupal\autosave_form\Form\AutosaveFormBuilder->processForm('quiz_question_answering_form', Array, Object) (Line: 321)
Drupal\Core\Form\FormBuilder->buildForm('Drupal\quiz\Form\QuizQuestionAnsweringForm', Object) (Line: 97)
Drupal\autosave_form\Form\AutosaveFormBuilder->buildForm('Drupal\quiz\Form\QuizQuestionAnsweringForm', Object) (Line: 219)
Drupal\Core\Form\FormBuilder->getForm('Drupal\quiz\Form\QuizQuestionAnsweringForm', Object, Object) (Line: 201)
Drupal\quiz\Controller\QuizQuestionController->take(Object, '10')
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 573)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 124)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 151)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 68)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 52)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 708)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)