ErrorException:
Warning: Attempt to read property "value" on null

  at vendor/ibexa/taxonomy/src/lib/Event/Subscriber/ValidateTaxonomyEntryAssignmentSubscriber.php:75
  at Ibexa\Taxonomy\Event\Subscriber\ValidateTaxonomyEntryAssignmentSubscriber->onBeforeUpdateContent(object(BeforeUpdateContentEvent), 'Ibexa\\Contracts\\Core\\Repository\\Events\\Content\\BeforeUpdateContentEvent', object(TraceableEventDispatcher))
     (vendor/symfony/event-dispatcher/Debug/WrappedListener.php:117)
  at Symfony\Component\EventDispatcher\Debug\WrappedListener->__invoke(object(BeforeUpdateContentEvent), 'Ibexa\\Contracts\\Core\\Repository\\Events\\Content\\BeforeUpdateContentEvent', object(TraceableEventDispatcher))
     (vendor/symfony/event-dispatcher/EventDispatcher.php:230)
  at Symfony\Component\EventDispatcher\EventDispatcher->callListeners(array(object(WrappedListener)), 'Ibexa\\Contracts\\Core\\Repository\\Events\\Content\\BeforeUpdateContentEvent', object(BeforeUpdateContentEvent))
     (vendor/symfony/event-dispatcher/EventDispatcher.php:59)
  at Symfony\Component\EventDispatcher\EventDispatcher->dispatch(object(BeforeUpdateContentEvent), 'Ibexa\\Contracts\\Core\\Repository\\Events\\Content\\BeforeUpdateContentEvent')
     (vendor/symfony/event-dispatcher/Debug/TraceableEventDispatcher.php:154)
  at Symfony\Component\EventDispatcher\Debug\TraceableEventDispatcher->dispatch(object(BeforeUpdateContentEvent))
     (vendor/ibexa/core/src/lib/Event/ContentService.php:187)
  at Ibexa\Core\Event\ContentService->updateContent(object(VersionInfo), object(ContentUpdateStruct), array())
     (vendor/ibexa/core/src/lib/Repository/SiteAccessAware/ContentService.php:166)
  at Ibexa\Core\Repository\SiteAccessAware\ContentService->updateContent(object(VersionInfo), object(ContentUpdateStruct), array())
     (vendor/ibexa/admin-ui/src/lib/EventListener/ContentProxyCreateDraftListener.php:133)
  at Ibexa\AdminUi\EventListener\ContentProxyCreateDraftListener->translate(object(ContentProxyTranslateEvent), 'Ibexa\\Contracts\\AdminUi\\Event\\ContentProxyTranslateEvent', object(TraceableEventDispatcher))
     (vendor/symfony/event-dispatcher/Debug/WrappedListener.php:117)
  at Symfony\Component\EventDispatcher\Debug\WrappedListener->__invoke(object(ContentProxyTranslateEvent), 'Ibexa\\Contracts\\AdminUi\\Event\\ContentProxyTranslateEvent', object(TraceableEventDispatcher))
     (vendor/symfony/event-dispatcher/EventDispatcher.php:230)
  at Symfony\Component\EventDispatcher\EventDispatcher->callListeners(array(object(WrappedListener), object(WrappedListener)), 'Ibexa\\Contracts\\AdminUi\\Event\\ContentProxyTranslateEvent', object(ContentProxyTranslateEvent))
     (vendor/symfony/event-dispatcher/EventDispatcher.php:59)
  at Symfony\Component\EventDispatcher\EventDispatcher->dispatch(object(ContentProxyTranslateEvent), 'Ibexa\\Contracts\\AdminUi\\Event\\ContentProxyTranslateEvent')