I've got a Charge 3, the one with the oxygen sensor, and I've also seen it think I was asleep when I wasn't. On the other hand, it seems weirdly reliable at te

I've got a Charge 3, the one with the oxygen sensor, and I've also seen it think I was asleep when I wasn't. On the other hand, it seems weirdly reliable at telling if I'm in REM sleep or not. Whenever I wake up directly from what it says was REM sleep I remember my dreams but not otherwise.