I keep having the same error so I added this

if (event.request.cache === 'only-if-cached' && event.request.mode !== 'same-origin')
return
And all errors are gone :-) meanbee/magento-meanbee-pwa#20 (comment)

cdn/pwabuilder-serviceworkers/1.1.1/serviceWorker2/src/pwabuilder-sw.fixed.js

@@ -39,7 +39,15 @@ self.addEventListener("fetch", function (event) {
 	};
 
 	event.waitUntil(updateCache(event.request));
+
+	/*!
+	 * https://github.com/meanbee/magento-meanbee-pwa/issues/20#issuecomment-497626347
+	 */
 
+	if (event.request.cache === "only-if-cached" && event.request.mode !== "same-origin") {
+		return;
+	}
+
 	event.respondWith(
 		fetch(event.request).catch (function (error) {
 			console.log("[sw.js] Network request Failed. Serving content from cache: " + error);

libs/serguei-muicss/js/bundle.js

@@ -1924,7 +1924,7 @@ WheelIndicator, Ya*/
 			};
 			if (instagramMedia) {
 				if (!root.instgrm) {
-					var jsUrl = "https://www.instagram.com/embed.js";
+					var jsUrl = "https://platform.instagram.com/en_US/embeds.js";
 					var load;
 					load = new loadJsCss([jsUrl], initScript);
 				} else {

libs/serguei-muicss/src/bundle.js

@@ -1924,7 +1924,7 @@ WheelIndicator, Ya*/
 			};
 			if (instagramMedia) {
 				if (!root.instgrm) {
-					var jsUrl = "https://www.instagram.com/embed.js";
+					var jsUrl = "https://platform.instagram.com/en_US/embeds.js";
 					var load;
 					load = new loadJsCss([jsUrl], initScript);
 				} else {

sw.js

@@ -40,6 +40,15 @@ self.addEventListener("fetch", function(event) {
 	};
 
 	event.waitUntil(updateCache(event.request));
+
+	/*!
+	 * https://github.com/meanbee/magento-meanbee-pwa/issues/20#issuecomment-497626347
+	 */
+
+	if (event.request.cache === "only-if-cached" && event.request.mode !== "same-origin") {
+		return;
+	}
+
 	event.respondWith(
 		fetch(event.request).catch(function(error) {
 			console.log(