When a tag is not found, there is a warning.
Warning: Invalid argument supplied for foreach() in Drupal\views\Plugin\views\query\Sql->getAllEntities() (line 1703 of /var/www/docroot/core/modules/views/src/Plugin/views/query/Sql.php) #0 /var/www/docroot/core/includes/bootstrap.inc(584): _drupal_error_handler_real(2, 'Invalid argumen...', '/var/www/docroo...', 1703, Array) #1 /var/www/docroot/core/modules/views/src/Plugin/views/query/Sql.php(1703): _drupal_error_handler(2, 'Invalid argumen...', '/var/www/docroo...', 1703, Array) #2 /var/www/docroot/core/modules/views/src/Plugin/views/query/Sql.php(1689): Drupal\views\Plugin\views\query\Sql->getAllEntities() #3 /var/www/docroot/core/modules/views/src/Plugin/views/cache/CachePluginBase.php(260): Drupal\views\Plugin\views\query\Sql->getCacheMaxAge() #4 /var/www/docroot/core/modules/views/src/Plugin/views/display/DisplayPluginBase.php(2142): Drupal\views\Plugin\views\cache\CachePluginBase->getCacheMaxAge() #5 /var/www/docroot/core/modules/views/src/Plugin/views/display/DisplayPluginBase.php(2160): Drupal\views\Plugin\views\display\DisplayPluginBase->applyDisplayCacheabilityMetadata(Array) #6 /var/www/docroot/modules/custom/sony_cgd_rest_api/src/Plugin/views/display/SonyCGDRestExportNested.php(86): Drupal\views\Plugin\views\display\DisplayPluginBase->applyDisplayCachablityMetadata(Array) #7 /var/www/docroot/core/modules/views/src/ViewExecutable.php(1533): Drupal\sony_cgd_rest_api\Plugin\views\display\SonyCGDRestExportNested->render() #8 /var/www/docroot/core/modules/rest/src/Plugin/views/display/RestExport.php(441): Drupal\views\ViewExecutable->render() #9 /var/www/docroot/core/modules/views/src/ViewExecutable.php(1630): Drupal\rest\Plugin\views\display\RestExport->execute() #10 /var/www/docroot/core/modules/views/src/Element/View.php(77): Drupal\views\ViewExecutable->executeDisplay('sony_cgd_rest_a...', Array) #11 [internal function]: Drupal\views\Element\View::preRenderViewElement(Array) #12 /var/www/docroot/core/lib/Drupal/Core/Render/Renderer.php(378): call_user_func(Array, Array) #13 /var/www/docroot/core/lib/Drupal/Core/Render/Renderer.php(195): Drupal\Core\Render\Renderer->doRender(Array, true) #14 /var/www/docroot/core/lib/Drupal/Core/Render/Renderer.php(139): Drupal\Core\Render\Renderer->render(Array, true) #15 /var/www/docroot/core/lib/Drupal/Core/Render/Renderer.php(582): Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}() #16 /var/www/docroot/core/lib/Drupal/Core/Render/Renderer.php(140): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure)) #17 /var/www/docroot/core/modules/rest/src/Plugin/views/display/RestExport.php(424): Drupal\Core\Render\Renderer->renderRoot(Array) #18 /var/www/docroot/core/modules/views/src/Routing/ViewPageController.php(52): Drupal\rest\Plugin\views\display\RestExport::buildResponse('rest_api_progra...', 'sony_cgd_rest_a...', Array) #19 [internal function]: Drupal\views\Routing\ViewPageController->handle('rest_api_progra...', 'sony_cgd_rest_a...', Object(Drupal\Core\Routing\RouteMatch)) #20 /var/www/docroot/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array(Array, Array) #21 /var/www/docroot/core/lib/Drupal/Core/Render/Renderer.php(582): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #22 /var/www/docroot/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(124): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure)) #23 /var/www/docroot/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) #24 /var/www/docroot/vendor/symfony/http-kernel/HttpKernel.php(151): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #25 /var/www/docroot/vendor/symfony/http-kernel/HttpKernel.php(68): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1) #26 /var/www/docroot/core/lib/Drupal/Core/StackMiddleware/Session.php(57): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #27 /var/www/docroot/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #28 /var/www/docroot/core/modules/page_cache/src/StackMiddleware/PageCache.php(99): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #29 /var/www/docroot/core/modules/page_cache/src/StackMiddleware/PageCache.php(78): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true) #30 /var/www/docroot/modules/contrib/jsonapi/src/StackMiddleware/FormatSetter.php(45): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #31 /var/www/docroot/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\jsonapi\StackMiddleware\FormatSetter->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #32 /var/www/docroot/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(52): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #33 /var/www/docroot/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #34 /var/www/docroot/core/lib/Drupal/Core/DrupalKernel.php(693): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #35 /var/www/docroot/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request)) #36 {main}.