Error Thrown: mercury_editor_ajax_render_alter()

Problem/Motivation

An error is thrown

Deprecated ):function: strpos( Passing null to parameter #1 ($haystack) of type string is deprecated in v() (line 59 of modules/contrib/mercury_editor/mercury_editor.module).

mercury_editor_ajax_render_alter(Array, NULL, NULL) (Line: 545)
Drupal\Core\Extension\ModuleHandler->alter('ajax_render', Array) (Line: 204)
Drupal\Core\Ajax\AjaxResponseAttachmentsProcessor->buildAttachmentsCommands(Object, Object) (Line: 117)
Drupal\Core\Ajax\AjaxResponseAttachmentsProcessor->processAttachments(Object) (Line: 62)
Drupal\Core\EventSubscriber\AjaxResponseSubscriber->onResponse(Object, 'kernel.response', Object)
call_user_func(Array, Object, 'kernel.response', Object) (Line: 111)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.response') (Line: 652)
Drupal\big_pipe\Render\BigPipe->filterResponse(Object, 2, Object) (Line: 630)
Drupal\big_pipe\Render\BigPipe->filterEmbeddedResponse(Object, Object) (Line: 580)
Drupal\big_pipe\Render\BigPipe->sendPlaceholders(Array, Array, Object) (Line: 305)
Drupal\big_pipe\Render\BigPipe->sendContent(Object) (Line: 112)
Drupal\big_pipe\Render\BigPipeResponse->sendContent() (Line: 423)
Symfony\Component\HttpFoundation\Response->send() (Line: 20)