I have not heard of “H+ corrosion” unless they are referring to some sort of attack by an acid. There are various forms of corrosion generally classified as “hydrogen attack” but these involve elemental hydrogen (H2) and not hydrogen ions. I am not familiar with the chemistry you are running so it is difficult to answer your question with any certainty. Pitting and cracking of austenitic stainless steels like 316 are most often caused by halides especially chlorides. Do you have chlorides present? Even low (ppm) levels can be problematic under the right conditions. Even if you cannot determine the exact cause of the corrosion, you might be able to design and run lab and/or production experiments using coupons of more resistant alloys to check for corrosion resistance. Especially if you are simulating a production environment in the lab, I would also include 316 stainless steel coupons as a sort of control. Corroding of the 316 coupons would confirm you are satisfactorily simulating the corrosive environment.