Another data point, recently got miles credited to my Delta SM from my JFK-MEX flights (end of Feb-beginning of March), almost 3 months to be exact. Anyone looking at major mileage accruals with AM (especially AM to DL) needs be ready to wait out.
BTW this fare is long gone and got necro bumped. Anyway, we should see more deals from AM later, just be ready to deal with AM/DL.