Undefined index: base_plugin_label in DynamicEntityReferenceItem->targetTypeFieldSettingsForm

There's an undefined index, base_plugin_label when editing a field, e.g. at /en/admin/structure/activity/settings/fields/activity.activity.field_activity_entity.

Here's the full backtrace:

Notice: Undefined index: base_plugin_label in Drupal\dynamic_entity_reference\Plugin\Field\FieldType\DynamicEntityReferenceItem->targetTypeFieldSettingsForm() (line 310 of /app/web/modules/contrib/dynamic_entity_reference/src/Plugin/Field/FieldType/DynamicEntityReferenceItem.php)

#0 /app/web/core/includes/bootstrap.inc(312): _drupal_error_handler_real(8, 'Undefined index...', '/app/web/module...', 310)
#1 /app/web/modules/contrib/dynamic_entity_reference/src/Plugin/Field/FieldType/DynamicEntityReferenceItem.php(310): _drupal_error_handler(8, 'Undefined index...', '/app/web/module...', 310, Array)
#2 /app/web/modules/contrib/dynamic_entity_reference/src/Plugin/Field/FieldType/DynamicEntityReferenceItem.php(268): Drupal\dynamic_entity_reference\Plugin\Field\FieldType\DynamicEntityReferenceItem->targetTypeFieldSettingsForm(Array, Object(Drupal\Core\Form\FormState), 'group')
#3 /app/web/core/modules/field_ui/src/Form/FieldConfigEditForm.php(117): Drupal\dynamic_entity_reference\Plugin\Field\FieldType\DynamicEntityReferenceItem->fieldSettingsForm(Array, Object(Drupal\Core\Form\FormState))
#4 /app/web/core/lib/Drupal/Core/Entity/EntityForm.php(106): Drupal\field_ui\Form\FieldConfigEditForm->form(Array, Object(Drupal\Core\Form\FormState))
#5 [internal function]: Drupal\Core\Entity\EntityForm->buildForm(Array, Object(Drupal\Core\Form\FormState))
#6 /app/web/core/lib/Drupal/Core/Form/FormBuilder.php(532): call_user_func_array(Array, Array)
#7 /app/web/core/lib/Drupal/Core/Form/FormBuilder.php(278): Drupal\Core\Form\FormBuilder->retrieveForm('field_config_ed...', Object(Drupal\Core\Form\FormState))
#8 /app/web/core/lib/Drupal/Core/Controller/FormController.php(73): Drupal\Core\Form\FormBuilder->buildForm(Object(Drupal\field_ui\Form\FieldConfigEditForm), Object(Drupal\Core\Form\FormState))
#9 [internal function]: Drupal\Core\Controller\FormController->getContentResult(Object(Symfony\Component\HttpFoundation\Request), Object(Drupal\Core\Routing\RouteMatch))
#10 /app/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array(Array, Array)
#11 /app/web/core/lib/Drupal/Core/Render/Renderer.php(578): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
#12 /app/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(124): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure))
#13 /app/web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array)
#14 /app/vendor/symfony/http-kernel/HttpKernel.php(158): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
#15 /app/vendor/symfony/http-kernel/HttpKernel.php(80): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1)
#16 /app/web/core/lib/Drupal/Core/StackMiddleware/Session.php(57): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#17 /app/web/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#18 /app/web/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#19 /app/web/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(52): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#20 /app/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#21 /app/web/core/lib/Drupal/Core/DrupalKernel.php(717): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#22 /app/web/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request))
#23 {main}