Adding my voice to the many reports of sleep discrepancies. VivoActive 3 Music. For weeks now (since I started wearing the watch at night again), I noticed that Garmin Connect presents my sleep as alternating Light and REM sleep, with sometimes only a very brief period of Deep sleep at the start of the night. This does not reflect how I feel I've slept.
This morning, I happened to check my sleep stats immediately after waking. My Connect ap showed over 3hrs of Deep sleep distributed throughout the night, more in the first half than the second, and periods of Light and REM sleep, which looked like a normal sleep pattern to me.
Then, less than an hour later, all but the first half hour of Deep sleep had disappeared, apparently reassigned as light sleep and perhaps a bit of REM.
So now I'm wondering: how does Garmin do this? Why does a plausible sleep registration get re-analyzed, and then change into a much less plausible chart?