"awesome" KB 107 surprise

The pistons that have the relief on the edges are the newer design. The more normal looking pistons/valve reliefs are the older design.
That is not a problem with the pistons, you just need a set of the same 8 style. They will send you back pistons with relief on the edges of the valve pockets.
I run alot of KB pistons and almost never have any problems with them. Infact the only problem I DO have once in a while is I find ding's on the ring lands not allowing the rings to go into the land.
That's a handling issue not a manufacturing issue.