Second time this bug has happened to me so figured I’d post to see if anyone else has had it.
After about an hour play session of running through PoF on Legendary and clearing both bannermen, when I return to the gatekeeper it gives me the checkmark for the quest, but then the gatekeeper text doesn’t come up. The camera stays on him and then comes back to me but I’m unable to move or access inventory. Thankfully both times I could go to main menu and save/quit without losing any progress, so no harm done! Just a hiccup I wanted to point out.
Edit: Upon reloading my game the previously full Burst meter has been depleted. But looks like all items acquired throughout are still there.