I also just remembered that at one point before the poor tracking showed up, that my rotator came loose. I then tightened it quite snug. Maybe that was the culprit?
I absolutely would suspect rotator (and other equipment) attachment to the OTA before I would suspect rain or ground movement shifting the pier 4-6 degrees.
For peace of mind, I recommend pressing a level against the pier on two sides to determine if it is plumb or not. --- Mike
