Reaper, I’ve been doing a pork shoulder or leg on a foiled pan and tented with a sheet of foil for nearly 40 years with no problems and the way most cooks down here do it. I primarly cook Cuban and sour orange/salt/garlic/pepper/oregano/cumin is the primary marinade or paste to many of my meat and poultry dishes. I don’t marinate in foil, just in bake in the oven. While you’re technically correct and it should be reactive in theory, I have never seen any degradation and only a little discoloration to the foil where it touches the top of the fat cap on a leg or shoulder after many hours of baking. I often do my BBQ ribs like this in a pan with some water on the bottom and sealed with foil over the top prior to finishing under the broiler. In that case, the tomato bbq sauce will indeed cause some pitting and pinholes in the thinner top foil. It doesn’t seem to be the case with the mojo.