!!! This issue is relevant not only for the "IP address" field type, but also for other field types provided by core, like Text and Boolean.
On Drupal 11.0.5 after adding a new field to a content type the following error message appears:
Error message
Deprecated function: mb_strtolower(): Passing null to parameter #1 ($string) of type string is deprecated in Drupal\Core\Config\Entity\Query\Condition->compile() (line 39 of core/lib/Drupal/Core/Config/Entity/Query/Condition.php).
Drupal\Core\Config\Entity\Query\Condition->compile() (Line: 88)
Drupal\Core\Config\Entity\Query\Query->execute() (Line: 307)
Drupal\Core\Config\Entity\ConfigEntityBase->preSave() (Line: 272)
Drupal\Core\Entity\EntityDisplayBase->preSave() (Line: 528)
Drupal\Core\Entity\EntityStorageBase->doPreSave() (Line: 483)
Drupal\Core\Entity\EntityStorageBase->save() (Line: 239)
Drupal\Core\Config\Entity\ConfigEntityStorage->save() (Line: 354)
Drupal\Core\Entity\EntityBase->save() (Line: 614)
Drupal\Core\Config\Entity\ConfigEntityBase->save() (Line: 35)
Drupal\field_ui\Form\FieldConfigEditForm->configureEntityFormDisplay() (Line: 397)
Drupal\field_ui\Form\FieldConfigEditForm->save()
call_user_func_array() (Line: 105)
Drupal\Core\Form\FormSubmitter->executeSubmitHandlers() (Line: 43)
Drupal\Core\Form\FormSubmitter->doSubmitForm() (Line: 589)
Drupal\Core\Form\FormBuilder->processForm() (Line: 321)
Drupal\Core\Form\FormBuilder->buildForm() (Line: 48)
Drupal\Core\Entity\EntityFormBuilder->getForm() (Line: 62)
Drupal\field_ui\Controller\FieldConfigAddController->fieldConfigAddConfigureForm()
call_user_func_array() (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 593)
Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 121)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext() (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 183)
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: 32)
Drupal\big_pipe\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: 709)
Drupal\Core\DrupalKernel->handle() (Line: 19)
Active
2.0
Code
I can't reproduce this by installing an 11.0.5 site and adding a new field to a content type. So, the conditions to trigger the bug need some investigation. For that we need additional steps to reproduce it added to the issue summary.
I am removing the link to an issue that doesn't seem actually related.
Changes are made on on 11.x (our main development branch) first, and are then back ported as needed according to our policies.