Boy am I glad you pointed this out. That'll teach me for not checking my mileage statements closely enough! NONE of my pure MX flights (MX flight #, w/ AA# printed out on the boarding pass -- even passes for MX flights printed out on AA ticket stock) have posted. The only one that did post was one I flew as an AA codeshare. These flights go back all the way to June, so it's not a matter of delayed postings. 0 out of 8 for me.
Just called AA to have them verify, and nope -- nothing. Faxing them in now, but it sounds like there is a big bug in the system.
Again, thanks!