I recently upgraded my Edge 820 from V10 to V11. It also upgraded the GPS firmware. The track distance and speed are incorrect since the upgrade. The device constantly pauses during registration (pause symbol on display to play symbol on display, and vice versa).
I did a ride of 103 km (registered via Strava App on iPhone and confirmed by co-rider) and it only registered 28km (https://connect.garmin.com/modern/activity/3394440878). Average speed is 5,7 km/h, although it was about 22 km/h.
I have got a Stages power meter (firmware 2.0.86) and also the Garmin Varia RTL501 connected to the device. As heart rate sensor I use Wahoo TICKR.
I'm also using Garmin Forerunner 735XT with firmware 9.40 which registered only 54 km (https://connect.garmin.com/modern/activity/3394435081). This device has a similar issue. Both devices Forerunner and Edge did receive recently a new firmware upgrade. Ever since there's this annoying problem. Please advise how to resolve this issue.