[ol'George]

the tensioners are made of aluminum and they can bend slightly.
Usually the outside shaft support/bearing tips forward because of a thrown chain or just the constant pulling on it as it is closest to the chain.
That causes the sprocket to walk to that side and dig into the support.
At least it was on mine.
When I put on a new sprocket I put a washer between it and the tensioner to take some of the side thrust of the sprocket.
on my Qa 42A, the 24 tooth auger sprocket is welded to the auger so it might take some doing if a fellow wanted to replace it.