Night sleep was replaced by a 2.5h nap (and the nap wasn’t that long in reality because I discovered the watch though I still slept about 30mins after waking up)

I have also encountered this problem. I am though a night shift worker and find it very useful that the watch actually is capable of detecting daytime sleep even though it happens outside the pre set sleep window. However, I also think there’s a design flaw in the way a nap can replace a nights sleep and a possible solution would be to add a prompt where you can manually choose if the nap should replace the previously recorded sleep 

But then you as a night worker would be always prompted for your normal sleep? So I guess this should be optional? How active is your night work? Is the watch trying to give you as sleep during your work time? 

I don't work a lot of nights and I work at a hospital and therefore have to keep my watch in my pocket and not on my wrist. So sleep haven't been triggered during my night shifts before. Because I work nights quite seldom I never bother to change the sleep windo (which is set at 23.00-07.00 every day). So I therefore hope this thread doesn't lead to Garmin making the watch never detect sleep outside of the sleep window, but rather gives us an option to choos if we want the nap or the nighttime sleep to be the registrered one

SASNo said:

a possible solution would be to add a prompt where you can manually choose if the nap should replace the previously recorded sleep

I don't agree this should be an option at all. Why would a nap replace any previous sleep? Sleep should be additive.

Because the watch can detect sleep when you are not sleeping, but rate it as very poor sleep, and therefore degrade your sleep "performance", you should be able to start, save, discard, delete, trim sleep periods just like you do for activities without further damage to other sleep (just like any activity). Just like MoveIQ, the watch could detect sleep on its own, but unlike MoveIQ, you should be able to save, reject or delete a posteriori this automatically detected sleep if you wish to.

Whenever you edit your sleep, your sleep score, history, HRV, stress should be edited accordingly, and your metrics (eg Training Readiness) should be updated. At the end of day, we count on the watch to accurately reflect our activities and our rest.

I rather meant that I don't want garmin to make the watch stop detecting sleep outside the sleep window but rather have a prompt after waking up after sleep outside the sleep window asking if this was the main sleep or not. Did not mean that I ever want a 1h nap replace 8h sleep. And I agree with you on the rest of the comment. 

Here again. I was working, which means sitting at a computer for me. Nighttime sleep got replaced by 2.5 hours which it "detected". I set the time back to the original time, but the score stayed low. (And I'm pretty sure I didn't sit for 2.5 hours. I'm walking around quite often.)

If you have naps less than 3 hours that are being recorded by your watch that replace your prior nighttime sleep synced, I am gathering more information. Please highlight my name and send me a Private Message. Thank you!

Tell me, is the clock trying to screw with me? Now it has recorded sleep again this afternoon, although I typed a lot of text on the laptop. Second time today. That can't be!!! Two times sleep although I was awake. You can see how long I was awake. Heart rate quite normal. What is the clock doing there?