Now I''ve read that I may have to agree with the both of you.
As the crimping causes the piston to go slightly out of round (and yes it does) would any out of "roundness" cause pressure points to try and force the piston back "round " and thereby loosen the effect and integrity of the crimp ?
Given that the suggestion is that the crimp may only just retain the rod, I think this is highly possible
I for one take these high points off on all mine so hopefully no issues