After a stay in early Feb. had not posted by late Feb., I wrote a letter, and the missing stay posted a couple of weeks later. The weird thing was, the line item had the wrong location (RI La Jolla vs. RI Philly airport). I figured it was a harmless typo.
Then, a couple of weeks after that, the original stay posted with the correct location. (But the wrong location for those dates remained.)
I don't know if they'll catch it -- it was 6 nights, and it might make the difference for making Gold this year for me.
I might feel a little guilty if that happened...but not too much, since it was their fault.