Do you all really go straight to Marriott CS when trying to resolve these issues? I make a point of getting the business card of someone in the FD or lounge with a decent job title so that I can email them directly if the stay doesn't post or posts incorrectly. In my experience since the merger it's quite possible for stays to post within 48 hours of check out (happens almost 100% of the time for me) so if it's wrong then I email the named person directly within a few days of checking out thanking them for such a great stay etc. and asking them to fix it. Works 100% of the time for me without having to engage with CS. On the one occasion that nothing posted, I waited about a week before emailing the FD person I had chatted to (it was a Design Hotel in Mexico). Posted next day. I am beginning to believe that these things are largely manual errors on the part of the hotels that the hotels can fix. But I may be wrong and it's all random IT flashes.