Error message

Deprecated function: preg_match_all(): Passing null to parameter #2 ($subject) of type string is deprecated in Drupal\Core\Utility\Token->scan() (line 293 of core/lib/Drupal/Core/Utility/Token.php).

Drupal\Core\Utility\Token->scan(NULL) (Line: 66)
token_default_tokens_alter(Array, Array, Object) (Line: 562)
Drupal\Core\Extension\ModuleHandler->alter('tokens', Array, Array, Object) (Line: 366)
Drupal\Core\Utility\Token->generate('term', Array, Array, Array, Object) (Line: 239)
Drupal\Core\Utility\Token->doReplace(1, '[term:description]', Array, Array, Object) (Line: 189)
Drupal\Core\Utility\Token->replace('[term:description]', Array, Array, NULL) (Line: 66)
Drupal\metatag\MetatagToken->replace('[term:description]', Array, Array) (Line: 769)
Drupal\metatag\MetatagManager->processTagValue(Object, Array, Array, , 'en') (Line: 615)
Drupal\metatag\MetatagManager->generateRawElements(Array, Object) (Line: 547)
Drupal\metatag\MetatagManager->generateElements(Array, Object) (Line: 520)
metatag_get_tags_from_route() (Line: 129)
metatag_page_attachments(Array) (Line: 313)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}(Object, 'metatag') (Line: 405)
Drupal\Core\Extension\ModuleHandler->invokeAllWith('page_attachments', Object) (Line: 314)
Drupal\Core\Render\MainContent\HtmlRenderer->invokePageAttachmentHooks(Array) (Line: 288)
Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 132)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object)
call_user_func(Array, Object, 'kernel.view', Object) (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.view') (Line: 174)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 81)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 191)
Drupal\page_cache\StackMiddleware\PageCache->fetch(Object, 1, 1) (Line: 128)
Drupal\page_cache\StackMiddleware\PageCache->lookup(Object, 1, 1) (Line: 82)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 707)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)