Like ctdls says, there isn't much to the oneway sprag and for one to fail..well there are only a couple of reasons. Contact point alignment is the #1 reason. This is usually because one or both of the shaft's bearings have play and it is common for the cover bearing to fail as they do not pre-grease them well...and that type of bearing "may" also have a problem spinning at crankshaft speeds which can be 7K+ at times...pretty high for a greased ball or roller bearing. The other reason other then being installed incorrectly is a damaged surface. Although there were some reports of the retainer parts coming apart but I think that can be attributed to an alignment issue.
I would insist the entire system be replaced..shaft, wet clutch, sprag, and both bearings..all of it...and have them repack that case bearing with high temp, high speed bearing grease.