My sleep window is set from 22:00 to 08:00. Most of the time the sleep tracking is very good, regardless of the time I go to bed, even between 21:00 and 02:00. Waking time varies rather less, and again the watch does a good job most of the time.
I also wear an Oura Ring 3 and Ringconn Gen 1, so I can cross check between devices if anything appears truly out of whack. Occasionally any one of them can throw a wobble, but I rarely need to correct any of them - maybe once or twice per month, assuming I notice. Usually I will only double check when I get an unusually low sleep score from one of them.
Rest periods don't automatically translates into "Sleep".
I agree that the situation looks weird but maybe you're taking something that relaxes you before you go to sleep? Or you're moving too much to trigger the sleep detection. It's better to contact Garmin, directly, as they can access your account and see if there's anything weird.
