I have the same issue. I think it is because the follower tries to check if it can walk on the tile and since the tile under the bridge should be impassable terrain, it tries to teleport to a "safe" location.
If anyone tries this in the newest version:
Replace " open_set_controls_ui if @sprites["option"].index == @options.length" with
"SetControls.open_ui if @sprites["option"].index == @options.length"
At least that's working for me :D
Does anyone else have a problem when they use Surf? Whenever I use Surf, my Pokémon gets enabled as sent out, regardless of the setting I chose. Is this my fault? And also, for some reason Gyarados only shows up in-doors or after touching a water tile