not my first rodeo with aluminum heads either, but it's not everyone's expertise. I'm trying to figure out what the heck could have happened. I just regret not doing the work myself.

I've been an aerospace machinist for 15 years, manual and cnc machinist for 10 before that. I grew up being a mechanic with fleet maintenance on 12 busses and lots of farm and construction equipment.
Like I said, not my first rodeo. And my comment about it not being everyone's expertise was about the guy who screwed up my engine somehow.
I currently have 3 psd trucks, 4 trucks with 460s, and 5 trucks with V10 in them. I've broken and replaced many exhaust studs in the v10 without this problem. No one I've talked to has been able to say "yeah, that's happened to me and it was..."