This only seems to happen for me when I have more than one set of teleporters in a room. Try removing them all and only placing down one set. Should work properly then.
Very strange. I just used my friend's and it teleported me to the right room.
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Never mind, it only worked for me. It didn't work for her...
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I think I've found a solution: they seem to work if you move them a couple times before attempting to re-enter through them. So if you move it each time before you enter them, it should work. That's what worked for my friend and I.
EDIT: Just wanted to show you guys this awesome bug I wish I had D:<