We recently updated our system and I think we also encountered a bug.
The calendar is one day longer than it should be. This means, for example, from 30/Nov to 7 (the same problem applies to all other ranges). Previously set, continuous time periods, starting Monday ending Friday, show 30/Nov to 6/Dec at the same time, so there is no submit button. But the periods can't be adjusted because they cannot overlap.
For now, there is a workaround for this, but I believe it needs to be resolved somehow.