I'm just as frustrated at these issues as most of you are. My team has been working on trying to identify the culprit - we believe an ad is at play, but the ad creatives have been sneaky in hiding their tracks and we're sifting through terabytes of telemetry data that could potentially lead into finding the culprit. Once we do, we'll block it and go after the folks who designed it so we can prevent from happening.
I apologize for the delay in getting this resolved. It has proven trickier than I expected. For those who do get this often, the idea thing would be have fiddler running at the same time and save the trace for my team to review, but it's a hard to ask of anyone so I'm pursuing the route of telemetry data analysis instead.