I was building a custom map with "non realistic" geometry. Something like JesperTheEnd had done. Here's a link to one of his videos how he explain one of those things:

https://www.youtube.com/watch?v=469wMsx3FXw

(I was to lazy to make a video on my own, sorry for that)

The problem in the latest Snapshot: Somehow the relative teleportation isn't "smooth" anymore. You can tell when you've got teleported, even if the room looks the same. I don't know, where this "lagg" comes from. I've tested it with high and low Video Settings, it was still there.