I called MR yesterday to find out why my bonus points did not post for a second stay from Sept 16-19. My first stay was (in a seperate hotel) on Sept 15 (checkout). They initially denied my bonus points because their view was that I checked in on September 14 (BEFORE the promo started).

I pressed them on the fact that the T&C's said September 15 as the start date AND my checkout date was September 15. They relented and posted my points pronto.

I do not know if you may have a similar issue.