I noticed for a few days that after I would charge the device and take it off it's charger, the HR sensor would be disabled until I restarted it. It was a really annoying glitch because I wouldn't notice until hours later. I have found that when disabling the lock screen password on the watch (setting it to 'none ') would make the issue disappear (still testing). If this issue changes I will post another comment here. Just wanted to put this on here in case anyone else has been experiencing the issue.
