samething happened to me twice.I'm afraid to tell you,the only fix i could find is to reload the page,altrought the experience wont dissappear

Yes, I have experienced this too. It happens when your session/login expires while you're in the middle of a battle... but I'm not sure why/how that would ever happen. :S The game looses track of who you are and who you're fighting, and just defaults to ALL THE THINGS. >_> I've had no luck trying to make this happen on purpose as a means to find the source of the bug, so fixing it has been pretty much impossible. I've only had the big actually happen to me like 5 times ever and I assure you I play the game more than anyone! I'm not even sure if it's a problem with the battle code, the login code, the browser, etc. etc. :(

Either way, thank you for reporting it and until I figure it out you can do as Metal Shark Player suggested and just reload the frame/page. Any experience you collected in battle should have already been saved, so it shouldn't be too bad... right? :S I'm so sorry...

This also happened to me a while ago before it updated. I saw some characters that weren't usable yet like Bass in the background.