After you kill the two ogres and fight your way down the stairs to the yellow bar vandal. If the first person in your team hits the next zone to do the long drop before everyone gets through the doorway portal, it despawns. Then whoever didn't manage to make it through in time has to wait until whoever did get through makes it to the boss fight to pull everyone forward. This is bad because not only does it grind gameplay to a halt for whoever gets left behind, but if someone intentionally gets ahead of everyone else for the sole purpose of despawning the portal, they can just start trolling the entire run causing everyone else to have to abort the strike.