I have successfully used an EdgeHD 11 with an Alt-Az mount since April of 2020 (purchase date). I recently submitted a ticket to Celestron tech support regarding image shift apparently related to Sky Safari 6 Pro software. By refreshing the app, the problem appeared to be resolved (I am using Mac OS on either an iPhone or iPad Pro). I replaced the focus motor while trying to figure out the problem, and purchased, but did not initially replace, the Celestron Wifi dongle.
However, I just began experiencing the same problem with Sky Portal. As soon as the app connects to the mount, it sounds like the mount motor in the left fork is engaged, even without any user directional or focus motor instructions. The image begins to shift, mostly up, but sometimes to the left, in the field. This continues after slewing with goto instructions or directional controls, or use of the focus motor. The mount motor engagement on the left-hand fork actually continues to sound like it is engaged even after the software app is itself disconnected! If I replace the Wifi Module, the problem continues to occur with a "tainted" app, either Sky Portal or Sky Safari Pro 6, but does not happen, at least for some time, with a newly downloaded version of either.
Just to repeat, when I delete the app, download a new version, and re-connect, the software and mount act as they should - no shift, and no mount motor engagement when not slewing. I now don't know from one night to the next how long it is going to hold before the whole image shift / runaway mount motor dance resurfaces. When it does, I am forced to refresh the app and hope I can get through a new, full Starsense alignment and calibration(s).
Any help here would be appreciated.