Issue from new - the Garmin FR 255 doesn't care if you're asleep then wakes you up with move alerts! Will have to turn them off as it's more of a hinderance than a help.
If you don't want your watch to remind you to get more active, you can disable those alerts. But you can also extend your regular sleeping hours, to keep it from disturbing your restitution.
I did do that but does it for every day of the week so don't get the morning report if it's set to 10am, if you could set weekend "typical sleep" times then that'd be a good feature