It appears that while in hover (switching seats from backseat/pilot control to frontseat/cpg control), the AI pilot ever so slightly moves to one direction instead of maintaining a steady hover. I have come to believe this has always been the cause of the reported TADS issue. I have not tested what would happen if (from the frontseat) the AI pilot is commanded to perform its hover... i.e. if this would stabilize it in space.
Scuby's post in TADS keeps slewing to right was marked as the answer