Intake coolant leak

I would think block deck, head milling, intake could all cause problems. But this is an untouched bottom end 130k miles with only new cam bearings and cam, new, not reman heads and 2 different new intakes. I just don't get it. Like I said 3 other engines set up almost exactly the same with exception of one has actual original EQ heads and the others were Odessa new heads. Tried these enginequest ones, only thing different