I have updated the Drupal core from 8.5.5 to 8.6.13.
I am getting this error when I am trying to access the site home page
The website encountered an unexpected error. Please try again later.
Error: Maximum function nesting level of '256' reached, aborting! in is_int() (line 331 of core/lib/Drupal/Component/Utility/NestedArray.php).
is_int('id') (Line: 331)
Drupal\Component\Utility\NestedArray::mergeDeepArray(Array) (Line: 295)
Drupal\Component\Utility\NestedArray::mergeDeep(Array, Array, Array) (Line: 76)
Drupal\Core\Block\BlockBase->setConfiguration(Array) (Line: 59)
Drupal\Core\Block\BlockBase->__construct(Array, 'system_breadcrumb_block', Array) (Line: 50)
Drupal\system\Plugin\Block\SystemBreadcrumbBlock->__construct(Array, 'system_breadcrumb_block', Array, Object, Object) (Line: 64)
Drupal\system\Plugin\Block\SystemBreadcrumbBlock::create(Object, Array, 'system_breadcrumb_block', Array) (Line: 21)
Drupal\Core\Plugin\Factory\ContainerFactory->createInstance('system_breadcrumb_block', Array) (Line: 76)
Drupal\Component\Plugin\PluginManagerBase->createInstance('system_breadcrumb_block', Array) (Line: 62)
Drupal\Core\Plugin\DefaultSingleLazyPluginCollection->initializePlugin('system_breadcrumb_block') (Line: 57)
Drupal\block\BlockPluginCollection->initializePlugin('system_breadcrumb_block') (Line: 80)
Drupal\Component\Plugin\LazyPluginCollection->get('system_breadcrumb_block') (Line: 45)
Drupal\block\BlockPluginCollection->get('system_breadcrumb_block') (Line: 83)
Drupal\Core\Plugin\DefaultSingleLazyPluginCollection->setConfiguration(Array) (Line: 99)
Drupal\Core\Plugin\DefaultSingleLazyPluginCollection->addInstanceId('system_breadcrumb_block', Array) (Line: 55)
Drupal\Core\Plugin\DefaultSingleLazyPluginCollection->__construct(Object, 'system_breadcrumb_block', Array) (Line: 34)
Drupal\block\BlockPluginCollection->__construct(Object, 'system_breadcrumb_block', Array, 'breadcrumbs_2') (Line: 156)
Drupal\block\Entity\Block->getPluginCollection() (Line: 145)
Drupal\block\Entity\Block->getPlugin() (Line: 135)
Drupal\block\BlockViewBuilder::buildPreRenderableBlock(Object, Object) (Line: 190)
Drupal\block\BlockViewBuilder::lazyBuilder('breadcrumbs_2', 'full', NULL)
call_user_func_array('Drupal\block\BlockViewBuilder::lazyBuilder', Array) (Line: 358)
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: 132)
__TwigTemplate_cf6437565d400c2322d9e99037ec649348d359f4adef0895fd06a0df4346be1c->doDisplay(Array, Array) (Line: 427)
Twig\Template->displayWithErrorHandling(Array, Array) (Line: 398)
Twig\Template->display(Array) (Line: 406)
Twig\Template->render(Array) (Line: 64)
twig_render_template('themes/lse_blue_theme/templates/system/page.html.twig', Array) (Line: 384)
Drupal\Core\Theme\ThemeManager->render('page', 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: 103)
__TwigTemplate_c069a9529aa6218d5824dd37cbaf30a21d7dfac280b2df820f4b8b395d834807->doDisplay(Array, Array) (Line: 427)