Sometimes "Any Time Dining" is not so great.
On a recent X cruise on the Constellation we had AT dining, we usually had dinner around 7pm.
On several nights we were put on a wait list, we usually had to wait up to 30 minutes but one night it was nearly 90 minutes, even though we were sailing with only a third of passengers.
I am assuming it was staffing, not sure.
Lol, on one night we discovered that at one table of 4 they were playing cards.