Are 800 XCR motors known for eating pistons?

After a long road with diagnosing my cousin's sled having a cylinder not firing, we finally pulled the pipes and looked at the piston.  To our suprise everything south of the ring lands was gone. almost not skirt left what so ever. This is a stock cylinder sled with stock pistons. Being a nice guy I donated my top end off of my xcr motor waiting for the race chassis to be built. The use of mine required swaping all three because they are ported. I thought I could use the pistons and found that two of the three pistons on my motor are cracked in the same manner. My question is if there were bad pistons that found there way into some xcrs or what cause this seem too much of a coinsidence.