I know what could have happened. It really happens randomly. Sometimes when you are in a room and someone enters it, you see the player for a short time totally off the door. Within ~0.5secs he is back on the door (well it´s kind of lag based). The same thing does happen in GHs aswell when you enter/leave a room.
Just like at the GH with the spar arena, you do sometimes get warped to the farm and you will take the Gralat being on the most top. Personally you don´t see it when you get "warped", but others can see that.

Hope this helped. It´s the only solution I could figure out. And this is really true, because that happened to me a lot of times.