This is a very small issue, and wouldn't really cause anybody any problems in practice, but I figure I might as well report it. In the arena, the spike gate of death is considered an enemy type, and placing a rogue's Entangling Trap upon it will cause the trap to trigger, and immediately start the arena timer, locking the area and disabling other party members from joining, even if the actual combat of the arena hasn't started yet. A simple way around this is to just not place traps on the gate, but the principle problem is that the gate shouldn't be an enemy type to begin with. Minor issue, very low priority in the grand scheme of things, but still an issue nonetheless.