The alignment studs are just that, only used to align the head during install...
I would just cut the top 1/8" off of the stud and round off the top edge...strange though that the same area failed before the deck as milled and the stud replaced.
What style of gasket did you use? Am I seeing some witness marks on the top of the pistons. Zero decking leaves only the thickness of the compressed gasket to provide quench area under the non chamber areas of the head....your .046 gasket thickness is appropriate to your street engine, but I suspect the thickness is greater where it failed due to lowered clamping pressure.
Lean conditions would provide a "white" residue on the valve heads...it also will contribute to an excess of cylinder heat and will lead to eventual failure.
Say safe...
