fix repetitive log issues

lib/hooks/hooks-frame.js

@@ -285,7 +285,7 @@ this.hooksFrame = this.hooksFrame || (() => {
 			window.IntersectionObserver = function () {
 				if (!warningIntersectionObserverDisplayed) {
 					console.warn("SingleFile is hooking the IntersectionObserver API to detect and load deferred images."); // eslint-disable-line no-console
-					warningRequestAnimationFrameDisplayed = true;
+					warningIntersectionObserverDisplayed = true;
 				}
 				const intersectionObserver = new IntersectionObserver(...arguments);
 				const callback = arguments[0];