Milk and milk products have lactic acid. It’s the acidity aggravating your GERD.
That is quite likely. I figured out a year or so ago that I was sensitive to milk, because I craved it in the middle of the night. Sounds weird, but that is one sign of a food sensitivity. I have continued eating cheese and ice cream and other dairy products. Last weekend we had some fresh mozzarela cheese, and my stomach was not happy! Still trying to figure things out. Any suggestions?