Notice: Undefined index: feeds_item_option in Drupal\feeds\Feeds\Target\EntityReference->buildConfigurationForm()

PHP: 5.6.33 (XAMPP Windows)
Drupal: 8.5.3

Feeds: 8.x-3.0-alpha1
Tamper: 8.x-1.x-dev updated 25 May 2018
Feeds Tamper: 8.x-2.x-dev updated 25 May 2018

Fetcher: Upload
Parser: CSV
Processor: Term (Taxonomy)
Processor settings: Update excisting ...

Fields:
- Term (set as unique)
- Plain Text
- Taxonomy Reference Field, Autocreate, (Tamper: Break up sequenced data into an array)
- Taxonomy Reference Field , Autocreate, (Tamper: Break up sequenced data into an array)
- Description

I found the following protocoll entry:

Notice: Undefined index: feeds_item_option in Drupal\feeds\Feeds\Target\EntityReference->buildConfigurationForm() (Zeile 328 in C:\xampp\htdocs\medikartei-8-1\modules\feeds\src\Feeds\Target\EntityReference.php) #0 C:\xampp\htdocs\medikartei-8-1\core\includes\bootstrap.inc(582): _drupal_error_handler_real(8, 'Undefined index...', 'C:\\xampp\\htdocs...', 328, Array) #1 C:\xampp\htdocs\medikartei-8-1\modules\feeds\src\Feeds\Target\EntityReference.php(328): _drupal_error_handler(8, 'Undefined index...', 'C:\\xampp\\htdocs...', 328, Array) #2 C:\xampp\htdocs\medikartei-8-1\modules\feeds\src\Form\MappingForm.php(225): Drupal\feeds\Feeds\Target\EntityReference->buildConfigurationForm(Array, Object(Drupal\Core\Form\FormState)) #3 C:\xampp\htdocs\medikartei-8-1\modules\feeds\src\Form\MappingForm.php(95): Drupal\feeds\Form\MappingForm->buildRow(Array, Object(Drupal\Core\Form\FormState), Array, 2) #4 [internal function]: Drupal\feeds\Form\MappingForm->buildForm(Array, Object(Drupal\Core\Form\FormState), Object(Drupal\feeds\Entity\FeedType)) #5 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\Form\FormBuilder.php(514): call_user_func_array(Array, Array) #6 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\Form\FormBuilder.php(364): Drupal\Core\Form\FormBuilder->retrieveForm('feeds_mapping_f...', Object(Drupal\Core\Form\FormState)) #7 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\Form\FormBuilder.php(621): Drupal\Core\Form\FormBuilder->rebuildForm('feeds_mapping_f...', Object(Drupal\Core\Form\FormState), Array) #8 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\Form\FormBuilder.php(314): Drupal\Core\Form\FormBuilder->processForm('feeds_mapping_f...', Array, Object(Drupal\Core\Form\FormState)) #9 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\Controller\FormController.php(74): Drupal\Core\Form\FormBuilder->buildForm(Object(Drupal\feeds\Form\MappingForm), Object(Drupal\Core\Form\FormState)) #10 [internal function]: Drupal\Core\Controller\FormController->getContentResult(Object(Symfony\Component\HttpFoundation\Request), Object(Drupal\Core\Routing\RouteMatch)) #11 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array(Array, Array) #12 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\Render\Renderer.php(582): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #13 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber.php(124): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure)) #14 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) #15 [internal function]: Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #16 C:\xampp\htdocs\medikartei-8-1\vendor\symfony\http-kernel\HttpKernel.php(151): call_user_func_array(Object(Closure), Array) #17 C:\xampp\htdocs\medikartei-8-1\vendor\symfony\http-kernel\HttpKernel.php(68): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1) #18 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\StackMiddleware\Session.php(57): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #19 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\StackMiddleware\KernelPreHandle.php(47): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #20 C:\xampp\htdocs\medikartei-8-1\core\modules\page_cache\src\StackMiddleware\PageCache.php(99): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #21 C:\xampp\htdocs\medikartei-8-1\core\modules\page_cache\src\StackMiddleware\PageCache.php(78): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true) #22 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\StackMiddleware\ReverseProxyMiddleware.php(47): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #23 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\StackMiddleware\NegotiationMiddleware.php(50): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #24 C:\xampp\htdocs\medikartei-8-1\vendor\stack\builder\src\Stack\StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #25 C:\xampp\htdocs\medikartei-8-1\core\lib\Drupal\Core\DrupalKernel.php(664): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #26 C:\xampp\htdocs\medikartei-8-1\index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request)) #27 {main}.