Regular hirers now show which nights didn't fit, and what's in the way
If a regular's slot clashes with another booking, that regular now says how many nights are missing and why.
What was wrong
When a regular's weekly slot overlapped a booking already in the room, those nights were left out of the diary. We said so once, straight after you saved, with a count for the whole hall rather than that hirer, and then the message went.
What's different now
The form lists the clashing dates before you save, and each regular on Regular hirers shows how many of its nights are missing and what is in the way until you sort it out. Undo on a week you'd moved, then given back, now puts back the moved night.
If this affected you
Open Diary, then Regular hirers, and look for a regular with nights missing. Move one of the two bookings or change a time.