Ironically, I could only get this to work in Edge (the new Edge which is Chromium underneath) by turning down the "Cache timer repetitions", the thing which is

Ironically, I could only get this to work in Edge (the new Edge which is Chromium underneath) by turning down the "Cache timer repetitions", the thing which is supposed to make timing differences more discernible. At only 500, it works every time. If I crank it up to 5000, it doesn't work at all.