Yeah, it could have been the slight drop in miles the last three months. My last two intl flights were to SIN on SQ through SFO/LAX which had me on AA for the domestic legs to the West coast from DFW. Sometimes the info for the SQ flights showed on AA.com so I know they could see I was flying SQ intl if they took the time to investigate.

Last time I had a mileage drop (due to a local project), I got the call and they directly asked where I had been and I did not get anything either. No questions asking why I was gone this time.

I don't want anyone else to feel slighted as I agree it is impossible to tell what "factors" made the decision. I was just curious if I missed a program like the Anniversary last year.