On certain areas (e.g. the flat area of Smooth Autumn), using the “set target” option on teleporters causes players to clip through the ground and fall under the map rather than arrive at the teleport destination properly.
Use the “set target” option on a teleporter to set a teleport target on the ground.
The player teleports to the location with the target at the player’s feet.
The player teleports to the location with the target at the center of the player capsule, and then falls through the map.
Bug happens no matter the player size, issue stems from how teleports are handled in the first place (teleport center of player to target and then let player collision push the player up to the ground, rather than teleporting the feet of the player to the target).