Just a thought, what about lack of coolant flow in that area?
Georges B.

It's pretty hard to have flow everywhere but one area, but I won't say it isn't possible.  With a pic of the exact area, we could make a better guess. 

FWIW, my money is on the rotor housing being narrow in that corner.  One of mine was just a tiny bit narrower on one spot, but that "worst case" area still made spec.  I hope he makes some good measurements before he puts it all back together. 

BTW, did we ever figure out where in LA he is?

Cheers,

Rusty