I run (almost) every day around Greenlake in Seattle. I use a Garmin watch to track those runs, and sure enough after the 1st my route appeared to be not so much around the lake as on the lake.

Side note, DCRainMaker is an incredible resource, and has dictated every one of my fitness device purchases for the last... 5 years? It's awesome they're so plugged in to the device landscape that they have a root cause for this bug, while not working directly on the fix.