This has happened to me multiple times both on PS3 and PSV.
I'll go into ranked match tournaments, pick my character and start searching for opponents.
On the screen where it shows who is who and their ranks, my character isn't who I chose?
I've had it go from Sly Cooper to Fat Princess, Raiden, Kratos, etc. This is very annoying and I can't find anything online about this problem. Am I the only one or what?
At least I'm not the only one I guess.
It seems to only happen when I find opponents, then search for new ones for whatever reasons, then find them again.
Just hit the circle button when it jumps to search for opponents if you can. Its what I do.