I had a recent experience of stay credit did not post after two weeks of a reward stay. Called the DD, I think they manually put a small incidental (few cents) and pushed the stay credit.

I have other reward stays with zero balances recently, they were post promptly with the Q2 bonus.

So I also think the problem of not posting stay credit is a issue with the hotel. Too bad the DD responded to OP seems not well trained to cause more confusion.