I looted a War Supply chest in Nazjatar and my achievement progress for Fighting On Two Fronts did not change from 2/5. I was the only one at the crate and am for sure the one that actually opened and then looted it.
October thread: Nazjatar War Crate not counting towards Fighting On Two Fronts achievements
January thread: Nazjatar War Crate not counting towards Fighting On Two Fronts achievements