huh
How exactly does that work... DOA doesn't exactly have saves, Besides Saves are embedded within the profiles so that would be a difficult trick to pull.
If you play 2 player though using a profile with a lot of achievements, quite often it will bestow your achievements on whoever beats you... My brother created a profile and we were playing some 2 player, we played about 8 or 10 matches in a row which I won. then he won and it gave him an "Achievement Unlocked Message" clicking the guide button it showed he's unlocked all of my story mode and played for X hours achievements
Not only that but I've heard of this exact same thing happening to several other people.
, i have read that what he is saying is the cause of the bug also (if another profile starts up the game, it overwrites the old info)
just checked your post date and the date of the post on the main page, and saw that you posted before that was up, sorry for pointing out something that everyone probably already knows