Possible Scott is remiss on not specing epoxy to keep Delrin bushings in place. In fact probable. A further dynamic is...if a Shimano crankset which has mechanical preload and not wavewasher which exerts preload based upon BB shell width and crank spindle tolerance...if a Shimano crank is set up too loose axially, this will promote dislodging of the Delrin bushings because in effect a hint of axial preload helps keep the bushings and bearings seated. Once the bushings come slightly loose, then cyclic pedal forces will cause the abrasive wear.