block_alter function does not work with Panelizer

I am using Panelizer (4.x) and when setting any panels to a node which view mode is Panelized I get this warning when viewing the node:

Notice: Undefined index: #id in at_core_theme_suggestions_block_alter() (line 115 of themes/contrib/adaptivetheme/at_core/includes/suggestions.inc).
at_core_theme_suggestions_block_alter(Array, Array, 'block') (Line: 453)
Drupal\Core\Theme\ThemeManager->alterForTheme(Object, 'theme_suggestions', Array, Array, 'block') (Line: 462)
Drupal\Core\Theme\ThemeManager->alter(Array, Array, Array, 'block') (Line: 245)
Drupal\Core\Theme\ThemeManager->render('block', Array) (Line: 437)
Drupal\Core\Render\Renderer->doRender(Array) (Line: 450)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array) (Line: 490)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 56)
__TwigTemplate_6bc2c2a4be03937decaa4eb1c0d39af747b44d5c7e30912d8db85c3fa5c28de6->doDisplay(Array, Array) (Line: 432)
Twig_Template->displayWithErrorHandling(Array, Array) (Line: 403)
Twig_Template->display(Array) (Line: 411)
Twig_Template->render(Array) (Line: 64)
twig_render_template('core/themes/stable/templates/layout/layout--onecol.html.twig', Array) (Line: 384)
Drupal\Core\Theme\ThemeManager->render('layout__onecol', Array) (Line: 437)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array) (Line: 490)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 92)
__TwigTemplate_593995916bb379c76ab4921d9bb62c05ef9b0a91f048a86c9efdd38d9e83a551->doDisplay(Array, Array) (Line: 432)
Twig_Template->displayWithErrorHandling(Array, Array) (Line: 403)
Twig_Template->display(Array) (Line: 411)
Twig_Template->render(Array) (Line: 64)
twig_render_template('modules/contrib/panelizer/templates/panelizer-view-mode.html.twig', Array) (Line: 384)
Drupal\Core\Theme\ThemeManager->render('panelizer_view_mode', Array) (Line: 437)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array, ) (Line: 226)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 576)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 227)
Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 117)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object) (Line: 108)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('kernel.view', Object) (Line: 158)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 68)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 99)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 78)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 50)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 657)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

It also breaks the "edit" button from the Panelizer UI JS. This Notice is shown once for each Panel on node when the mobile menu is shown.

The problem is in the line 115 which the notice suggests because if I comment the line out the mobile menu does not work at all. I can also fix the problem like this (because I know the menu #id which is mainnavigation):

// Use a custom block suggestion for responsive menus.
  if (isset($theme['path_skin'])) {
    // Skin themes need to use the base themes block elements id to match the config setting.
    $variables['elements']['#id'] = str_replace($theme['name'], $theme['base'], $variables['elements']['#id']);
  } else {
     $variables['elements']['#id'] = 'mainnavigation';
  }

Any ideas why this is happening and tips for a real patch?