This is something I have seen in only one other unit, (I've got 10+ years on these and have experience with 50+ different SRM's over the years, either with clients or my own inventory). That was in a Dura unit which was shifting because it had a non splined interface between the spider and the crank mount.

The auto offset isn't the issue (it's not stable enough for the auto offset to work), it's in the unit itself. Noting that it was dead stable for 2+ years. Just returned from SRM service, sent it in for this issue.

Try the stomp test in the video...one with the pedals going forward, one "backpedalling". See if the offset moves. In my case I was getting a 40 point swing, since service it's down to 20.