Vault of the Wardens: Demon's Bile quest is broken and can't be complete

The quest requires you to use a Legion potion called Skaggldrynk, when consumed inside Vault of the wardens, should allow you to pass a ward on a door. When I used the potion, no ward showed up meaning I couldn’t complete the quest. I tried this in every version of the instance to no avail. Does anyone know a way to get through the door without the potion or is this quest impossible to complete now?

From a WowHead comment from back in Shadowlands, there’s an undocumented maximum character level limit above which the potion won’t have any effect. Any DF player will probably be well beyond that limit.

I don’t see any way to do the quest except for a character in the Legion level band, but maybe someone else knows of something.

The potion says not very effective above level 50, I can still go into another plane at the door, but the ward itself doesn’t show up.