Error: Call to a member function render()

Problem/Motivation

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Error: Call to a member function render() on null in Drupal\paragraph_group\Paragroup\ParagroupFormData->getCurrentWidget() (line 195 of modules/contrib/paragraph_group/src/Paragroup/ParagroupFormData.php).
Drupal\paragraph_group\Paragroup\ParagroupFormData->getDetailsWidgetOption() (Line: 322)
Drupal\paragraph_group\Paragroup\ParagroupFormData->getDetailsWidgetOptions() (Line: 338)
Drupal\paragraph_group\Form\ParagroupConfigForm->getDetailsWidgetContent() (Line: 400)
Drupal\paragraph_group\Form\ParagroupConfigForm->detailsWidget() (Line: 545)
Drupal\paragraph_group\Form\ParagroupConfigForm->mainCheckboxElements() (Line: 584)
Drupal\paragraph_group\Form\ParagroupConfigForm->mainCheckboxes() (Line: 751)
Drupal\paragraph_group\Form\ParagroupConfigForm->buildForm()
call_user_func_array() (Line: 536)
Drupal\Core\Form\FormBuilder->retrieveForm() (Line: 284)
Drupal\Core\Form\FormBuilder->buildForm() (Line: 73)
Drupal\Core\Controller\FormController->getContentResult()
call_user_func_array() (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 638)
Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 124)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext() (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 181)
Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 53)
Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass() (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 36)
Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 741)
Drupal\Core\DrupalKernel->handle() (Line: 19)