I've had this happen numerous times. I'll get up, look at my sleep numbers, and decide to sleep a bit more. Then, when I wake up and check again, my recorded sleep patterns from earlier are all changed. Generally, it takes away deep and REM sleep that was previously recorded.
In other words, I can wake up at 5:30 and look at my numbers and it will tell me I got something like 35 minutes of deep sleep and an hour of REM over six hours or so. I go back to sleep, wake up around 7:30 and look at the numbers again -- and all or most of that deep and REM sleep is gone. It will now tell me I got only a few minutes of deep or REM sleep, or sometimes none at all.
What's going on?! I was either sleeping deeply or I wasn't right? I don't see how getting more sleep changes what happened before.
Frankly, I'm losing all faith in this thing tracking my sleep accurately at all because of this and times when I know I was awake or asleep and it reported otherwise.
