Missing messenger in EntityOverrideFormAlter

Error: Call to a member function addWarning() on null in Drupal\sites_group_overrides\FormDecorator\EntityOverrideFormAlter->entityFormSharedElements() (line 155 of modules/contrib/sites_group/modules/sites_group_overrides/src/FormDecorator/EntityOverrideFormAlter.php).

Nicht sicher, wo ihr den messenger Service unterbringen möchtet (EntityOverrideFormAlter oder im form_decorator).