If you have more than one Garmin Watch connected to the Garmin Connect Mobile app on your phone, you may have the following issues:
1. Critical Power and Stryd Power Zones not updating for the Stryd Zones data field on one of the Garmin watches
2. Not able to fetch workouts with the Stryd Workout app on one of the Garmin watches.
This is a limitation of the Garmin system. Only one instance of Stryd Zones and the Stryd Workout app can work at a time with one watch (no problem having both Stryd Zones and the Stryd Workout app on one watch).
If you have two watches, you can temporarily disable the connection with the phone on the watch itself (go to settings > phone and disable the connection), or by removing one of the watches from your Garmin Connect Mobile app (no data will be lost).