Found this by accidentally turning off my iOS device while running.
- start Zwift, select “Run”, in the bluetooth pairing screen set the treadmill speed to 8.0 km/h
- Using the Milestone Foot Pods, do a 60 second calibration run at treadmill setting 8.0 km/h
- start the run and watch your speed doing somewhat around 8.0 km/h
- turn device screen off and on again
- see speed indicating too high, somewhat around 10 km/h, the standard setting, app is ignoring the setting and the calibration run.
Setup: iPhone 6S Plus, iOS 11.2.6, Zwift 1.0.24186, Milestone Foot Pods and BT HR monitor paired