The setup was a 3" disc attached to the factory bump tower with a button head bolt holding it in place. On the bottom a there is a 2" tall tube that acts as a hard stop (top end rounded off, bottom end welded to a suitably sized washer) bolted to a 2" bump stop pad on the bottom spring perch. The tube holds the Prothane insert centered on the bottom pad. The axle was set to where the hard stops would hit the 3" discs about centered front to back about 3/4" off to the right.
There is some sign that the right side prothane may have been flexing over enough to get caught in the open top of the tube causing chunks of poly to be chewed out of the insert from the inside, but is seems the left one just came apart top to bottom. Not sure if the damage to the right insert was before or after the spring perch got bent.(It was a kind of rough day) The left insert has damage (cracking of the polyurethane) below the level of the top of the stop tube, so it couldn't have chunked out from flexing over the opening in the tube unless it was unseated when it was compressed and started to flex sideways before it was pushed down. I kind of don't see that happening, but I suppose it's possible.
As far as Prothanes taking the place of proper shock setup,.. well, we did loose both front shocks at between 100 and 150 miles, well after the Prothanes gave out.