Does the sleeping algorithm needs to recalibrate after the 8.11 update?

Awake time is now closer to what a Fitbit would show you, I think. Your watch should track even the short periods of awakening that a standard sleep cycle includes and which you (usually) don't remember in the morning.

"A National Institutes of Health study that found no statistical differences among gender in average frequency of awakenings. However, they did find that older individuals commonly awoke more frequently. In fact, the average number of awakenings hovers around six times per night. As the body cycles through various stages of sleep, including deep sleep and REM sleep, it dips from shallower to deeper states."
www.sleepscore.com/.../

I wear the Fitbit Charge 5 on my right wrist and the Venu 2S on my left.  The entire reason I wear the Fitbit is to more accurately monitor my sleep.  I started with the original Vivoactive and have used up to the Vivoactive 3 before going with the Venu 2.  The sleep tracking on the Vivoactive's were useless.  It has improved with the Venu 2 but it's still nowhere near as accurate as the Fitbit.  This morning the Venu 2 has me @ 4 minutes awake.  The Fitbit had me @ one hour and 29 minutes.  The Fitbit figure was way more accurate.  

For monitoring my other activities, I'm staying with the Venu 2.   Garmin doesn't charge for a subscription and I prefer Garmin Connect over Fitbit.

I said closer!

Indeed, sleep tracking ist better with Fitbit, but everything else (including especially heart rate with HIIT and muscle workouts) is much (much, much, much ...) worse. So no way I will return to Fitbit. At least sleep tracking ist somewhat reasonable now and the summarizing sleep scores are not so far from the ones my Fitbit was showing

For me, heart rate after update is more believable, as like steps.

But sleep data is something wrong, if 5.38 showed REM phase instead of awake, now 8.11 shows light sleep or awake instead of REM.
It's stupid, because i remember my dreams and if one has dreams must be in REM phase.

Waiting for 15.x firmware

Yeah same.. after update not showing REM phase. Even after hard reset..according to VENU2 no REM for me in two days. Was better before update.

I have the same problem. Low REM and a lot of awake time. What a crap.

Well I have 0 REM for past two days and dont have awake time even shen i was up and make a few steps..so..yeah. Very bad

Just an FYI.  If you haven't been to the "Quantified Scientist" on YouTube, it's worth a visit.  He's a post-doctoral scientist who tests various fitness trackers including most of Garmin & Fitbit's offerings.  He pretty much nails Garmin's problems with sleep patterns.

I watched those and what was odd was that the Vivomove is substantially more accurate.  Weird.