Unfortunately this is a Trinity explore issue. Can you give me the LevelAreaId of this map if possible? I may try to see whether I can do anything to it.
Sorry to say that a majority of the backtracks are Trinity explore issues. Either with an improper box point or with an improper parameter setting.
Doing a new rift already, so that's not possible I'm afraid :/
I'm fairly certain though that it's identical to the map where you have to kill that spider bitch in Act 3. If you recall that quest, there's a level where you first have to fight her "sisters" aka succubus. That's the level.