Warning: Array to string conversion in Drupal\Core\Render\Markup::create()

Same problem here, but the error message looks little bit differ:

Warning: Array to string conversion in Drupal\Core\Render\Markup::create() (line 36 of core/lib/Drupal/Component/Render/MarkupTrait.php).

My setup is:
Drupal 9.5.1
HTML Titles for Drupal 8 - 8.x-1.0-alpha2

Not able to reproduce. what is the exact flow to get that error, during node|block|taxonomy save.
My setup is:
Drupal : 9.4.8
PHP : 8.0.26
Mysql : 5.7.29

Here is the full error code:

Warning: Array to string conversion in Drupal\Core\Render\Markup::create() (line 36 of core/lib/Drupal/Component/Render/MarkupTrait.php).

Drupal\Core\Render\Markup::create(Array) (Line: 41)
html_titles_preprocess_block(Array, 'block', Array)
call_user_func_array('html_titles_preprocess_block', Array) (Line: 287)
Drupal\Core\Theme\ThemeManager->render('block', Array) (Line: 433)
Drupal\Core\Render\Renderer->doRender(Array, 1) (Line: 204)
Drupal\Core\Render\Renderer->render(Array, 1) (Line: 160)
Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}() (Line: 580)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 161)
Drupal\Core\Render\Renderer->renderPlain(Array) (Line: 175)
Drupal\Core\Render\Renderer->renderPlaceholder('', Array) (Line: 665)
Drupal\Core\Render\Renderer->replacePlaceholders(Array) (Line: 550)
Drupal\Core\Render\Renderer->doRender(Array, 1) (Line: 204)
Drupal\Core\Render\Renderer->render(Array, 1) (Line: 148)
Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}() (Line: 580)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 149)
Drupal\Core\Render\Renderer->renderRoot(Array) (Line: 279)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->renderPlaceholders(Object) (Line: 128)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments(Object) (Line: 45)
Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond(Object, 'kernel.response', Object)
call_user_func(Array, Object, 'kernel.response', Object) (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.response') (Line: 202)
Symfony\Component\HttpKernel\HttpKernel->filterResponse(Object, Object, 1) (Line: 190)
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: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 50)
Drupal\ban\BanMiddleware->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: 713)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

I'm not sure, but maybe in html_titles.module

$theme_registry['field__node__title']['path'] = drupal_get_path('module', 'html_titles') . '/templates';

should be replaced with:

  $theme_registry['field__node__title']['path'] = \Drupal::service('extension.list.module')->getPath('html_titles') . '/templates';

drupal-check

  Line   html_titles.module
 ------ -----------------------------------------------------------------------------
  15     Call to an undefined method Drupal\Core\Entity\EntityInterface::getTitle().
  16     Call to an undefined method Drupal\Core\Entity\EntityInterface::setTitle().
  23     Call to deprecated function drupal_get_path():
         in drupal:9.3.0 and is removed from drupal:10.0.0. Use
           \Drupal\Core\Extension\ExtensionPathResolver::getPath() instead.
  33     Call to an undefined method object::label().

also when I'm trying to access the /admin/structure/views/view/taxonomy_term

the error appears:
TypeError: array_key_exists(): Argument #2 ($array) must be of type array, Drupal\Core\StringTranslation\TranslatableMarkup given in html_titles_preprocess_page_title() (line 52 of modules/contrib/html_titles/html_titles.module).

Yes it was throwing the error on /admin/structure/views/view/taxonomy_term page , I update the code and working fine for me.
Please review the patch.

Dharmendra.s thank you for the patch, I could confirm it's working

Thanks!