I don't know if it was "custom" but yes, it was in Fel. It was just odd because typically you don't see things go in the Z direction (as opposed to a 2D XY grid). But this one you had to go under it to unlock, which you could get close enough, but I think you need to be 1 tile away to loot, which you couldn't get. So it was probably 2 tiles off the ground.
Hopefully that makes sense. It was in the exact same spot I've seen it before, but this time it was up high.