Was doing Twisted Domain (Breach Boss map), didn't die but ported back to beginning, Breach closed

As per title, I was doing my 3rd or 4th Breach Boss map.
I've done these before, no problem but this time, pretty close to the boss room, I was suddenly ported back to the beginning of the map (where you first start the Breach), and the usual loot spawned.

But the Breach was close, so therefor I lost access to the boss room.

Is that working as intended? Maybe it's that timer but I've seen the timer count to zero before and it didn't port me / close the Breach.