Jumping on the ledge at the boat finale during a run will cause zombies to get stuck and make zombie spawns cease to exist at the cannon part, so it's banned atleast for duos, trios and quads. If you accidentally did it in your run as long as your other teammate didn't and stays on the boat the zombies won't get stuck and the run is still valid. For runs that were verified before this rule change only a 5 second time penalty was added.