player.teleport will not teleport

[Xyphyn]

I have it so that when a game ends in a different instance, it sends them back to the lobby instance. In the lobby instance, I have this event:

instance.eventNode().addListener(AddEntityToInstanceEvent::class.java) {
val player = it.entity as? Player

        if (player != null) {
            player.setGameMode(GameMode.ADVENTURE)
            player.inventory.clear()
            player.teleport(spawn)
        }

}

The gamemode is correctly set to adventure, the inventory is cleared, but they are not teleported to spawn. Why is this? There is no error message or anything.

[GreatWyrm]

I would advise against teleporting someone as they are joining the instance, and you should use: Player#setInstance(instance, Point) instead.

That will work a lot better.