Move the required init functions to dedicated function with has run flag

src/frontendHighlighterApp/index.js

@@ -891,9 +891,19 @@ class AccessibilityCheckerHighlight {
 	}
 }
 
-window.addEventListener( 'DOMContentLoaded', () => {
-	new AccessibilityCheckerHighlight();
-	if ( window.edacFrontendHighlighterApp?.userCanFix ) {
-		fixSettingsModalInit();
+// Some systems (Cloudflare Rocket Loader) defers scripts for performance but that can
+// cause some DOMContentLoaded events to be missed. This is flag tracks if it run so we
+// can retry at a latter event listener.
+let initHasRun = false;
+const initHighlighter = () => {
+	if ( ! initHasRun ) {
+		new AccessibilityCheckerHighlight();
+		if ( window.edacFrontendHighlighterApp?.userCanFix ) {
+			fixSettingsModalInit();
+		}
+		initHasRun = true;
 	}
+};
+window.addEventListener( 'DOMContentLoaded', () => {
+	initHighlighter();
 } );