Usagov 1685 fix site banner

web/modules/custom/usa_twig_vars/usa_twig_vars.module

@@ -277,6 +277,8 @@ function usa_twig_vars_preprocess_views_view_list__federal_agencies(&$variables,
  */
 function usa_twig_vars_preprocess_region(&$variables) {
 
+  $state = \Drupal::state();
+
   // Check if we are in the `header_top` region
   if ($variables['region'] === 'header_top') {
 
@@ -299,11 +301,20 @@ function usa_twig_vars_preprocess_region(&$variables) {
           if ($place_above_header) {
             // Set the value to the site_banner id to add the site_banner to the `header_top` region.
             $variables['site_banners'][$site_banner->id()] = $site_banner->id();
+
+            // Clear the cache only if the block is not placed in the region and the "Place above header" checkbox is selected.
+            if (!$state->get('site_banners_placement.' . $site_banner->id(), FALSE)) {
+              $state->set('site_banners_placement.' . $site_banner->id(), TRUE);
+              drupal_flush_all_caches();
+            }
+
           }
           else {
             // Set the value to null to remove the site_banner with id `$site_banner->id()` from the region `header_top`
             $variables['site_banners'][$site_banner->id()] = NULL;
+            $state->set('site_banners_placement.' . $site_banner->id(), FALSE);
           }
+
         }
 
       }