My sleep tracking on 955 Solar isn't working either. I'm on the latest beta update.. but it hasn't worked for at least the last 3 updates I'd say. Sleep tracking and score will work as advertised on night .. then the next 3 or 4 won't record any sleep data...then one night it will...etc...very random, with sleep tracking not showing collected (on watch or in Connect app) probably 80 percent of the nights. I've rebooted many times, even but the bullet and did a factory reset but it didn't help.
I contacted support and gave them all the requested info and screenshots etc and they mentioned some other folk have reported sleep and health metrics problems and that I was being added to the ticket. Nothing since and I don't know where the issue stands, but I wanted to post here to make note if it in case others are having this happening. In general my health metrics have been a bit buggy, but the Sleep tracking seems to have it the worst.
