Afraid I wasn't able to make a screen recording, but on 2-3 occasions this morning, while on spotty Wi-Fi, we noticed a symptom whereby we'd written 2 lines of code in an app.js file, and all was well. We then added 2 more lines of code, but after a few seconds, those latter 2 lines suddenly disappeared from the editor. It seemed as though they were being echoed locally upon typing, but perhaps some save-to-server API call failed, at which point the error handler removed the new lines?