Brotherhood problems.

So i played (and loved) Assassins Creed 1 and 2. After putting the time in to 100% AC:II i decided Brotherhood was a must after learning that it was following on the story from number 2. After booting up the game and playing it for a couple of hours i was loving it more than i did it's predecessors. Until DNA sequence 5/6 when i was randomly desyncronized and sent to the main menu. I thought nothing of it and attempted to reload the game only to notice the 'single player' option was taken from my menu. I reloaded the entire game and although  my single player option was back, My save data was deleted from my 360's hard drive. Basically the point of this rant is, Back up your save around the time of killing the banker, Ubisoft have apparently patched this but better safe than sorry. My verdict, Awesome game - Bad bugs.