I did a rare run this morning, and as soon as I clicked ‘Run,’ my avatar took off at 25 km/h. I just watched, amazed, for a couple of minutes. Then I actually started running, and things went back to “normal.” Though I was running pretty steadily, my avatar would move in fits and starts. In all, my avatar covered 3.8 km in 20 minutes, but according to my treadmill, I ran only 2.4 km.
I use a Milestone footpod, last calibrated about a month or two ago. I use ZCA as a BLE bridge to Zwift running on Windows 10.