TypeError: mb_strlen(): Argument #1 ($string) must be of type string, array given in mb_strlen()

Problem/Motivation

TypeError: mb_strlen(): Argument #1 ($string) must be of type string, array given in mb_strlen() (line 102 of modules/contrib/office_hours/src/OfficeHoursDateHelper.php).
mb_strlen() (Line: 102)
Drupal\office_hours\OfficeHoursDateHelper::format() (Line: 196)
Drupal\office_hours\Element\OfficeHoursList::validateOfficeHoursSlot()
call_user_func_array() (Line: 282)
Drupal\Core\Form\FormValidator->doValidateForm() (Line: 238)
Drupal\Core\Form\FormValidator->doValidateForm() (Line: 238)
Drupal\Core\Form\FormValidator->doValidateForm() (Line: 238)
Drupal\Core\Form\FormValidator->doValidateForm() (Line: 238)
Drupal\Core\Form\FormValidator->doValidateForm() (Line: 118)
Drupal\Core\Form\FormValidator->validateForm() (Line: 588)
Drupal\Core\Form\FormBuilder->processForm() (Line: 320)
Drupal\Core\Form\FormBuilder->buildForm() (Line: 73)
Drupal\Core\Controller\FormController->getContentResult() (Line: 39)
Drupal\layout_builder\Controller\LayoutBuilderHtmlEntityFormController->getContentResult()
call_user_func_array() (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 564)
Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 124)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext() (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 158)
Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 80)
Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 58)
Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass() (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 50)
Drupal\ban\BanMiddleware->handle() (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 23)
Stack\StackedHttpKernel->handle() (Line: 708)
Drupal\Core\DrupalKernel->handle() (Line: 19)

I will arrange patch.