I've been meaning to report this but kept forgetting it, anyway I've noticed that dupes lately will try and go do a task in the short change from downtime to bedtime and generally end up wasting time that they could have been sleeping (more a problem for slower dupes).
My schedule has no work time between down time and bed time.
Steps to Reproduce
Watch your duplicants run off to go do tasks in the short period between down time and bedtime.
This issue has not been confirmed by a developer yet.