Post pic's of the rod bearing.
I'd think detention would take out the rod bearings 1st. That looks like either the caps are walking or the clearance is to tight on the middle caps.
One cannot tell if the caps are fitted properly by trying to move them by hand. The combustion process places hundreds, if not thousands, of pounds more force on them.
I agree, Jeremy, that detonation will take out the rods first and probably break the crank before it destroys the mains. I think the machine shop gets the blame on this one. Of course, they will assure you that they were perfect but we used to see a lot of these before we learned that the factory used a broaching cutter on the block and the aftermarket caps would not fit properly without reworking as Brad described.