could be, maybe different salt contents also. I would wonder if wrapping the meat tightly as opposed to my just covering the meat lug with 2 hot pork butts may play a part in it. Mine will have more moisture gathered at the top where the meat contacts the foil.

Not really sure, when I first started actually noticing it, I just figured salt is corrosive and it is even worse on aluminum when it is wet, factor in the warm humid environment I just subjected the foil to and that caused my pin holes.

Ribs wrapped, Iv never had happen. Every time in aluminum tray covered with foil. Last Saturday brisket one hole off to side and don't think was touching meat. Could be different rubs.