Stages SB 20 power meter fail mid ride

Today during Mary Austin my SB 20 paired and ran well until I was interrupted by a phone call. When I started again power readings were all over the place. I tried restarting the app, forgetting the SB20 and re-pairing, all to no avail. What solved the problem was going into the stages link app and zero calibrating the power meters. Posting in case someone else runs into this problem.

I had a similar problem today when the gearing b came none existent mid ride. I paired the bike in the link app and had to keep it open whilst using TR