Last week I notice that the body battery was off, then went to the gym and the heart rate reading was way too low (90s insteadon 130s+).
I followed the suggestion on this forum and did the soft restart. The body battery started to show a reasonable number and the HR during a run seemed reasonable.
After 5 days, it happened again.. I did the soft restart and it's working now.
Is there a more permanent fix? It seems like a software issue, would be great if I don't have to buy a new one.
If I don't realize there is an issue before starting a workout, the HR reading is useless. Which is very annoying. Alternatively, I have to do the restart every time I use it. Also annoying.