Are you playing in KR by any chance?
I noticed this the other day when I was playing in KR, except it wasn't when *I* switched, it was when anyone in the bank went from animal form to human (cant remember if it happened in reverse).
My game would "lag up" (for want of a better term) for several seconds. What I'd see would be the person who was changing, look like they were running on the spot for several seconds, nothing on the screen would move except the person who was "running on the spot", then my game would "unlag" and they'd be gone, and anyone else that had moved in the meantime had changed postitions too.
Was REALLY weird!