Borderlands 2 grants players “badass tokens” for completing challenges, which can be spent on stat upgrades.
Unfortunately, there is a bug in Borderlands 2 that could randomly reset your Badass total to 0 while still showing the challenges you took to earn those tokens as complete. This effectively locks the challenges out from being completed again, which means all your badass has been lost forever. When the bug occurs, it also wipes out all of your skins and all of your heads as well.
The bug seems to have something to do with save data corruption and seems to activate when backing out of the game after saving at certain points. You can tell it has affected you if the game acts like you are starting it up for the first time upon booting, even though your save file remains intact.
For now, the team at Gearbox is working on a fix, but they have not yet announced anything final. Users on the Gearbox forums have said you should take these steps to avoid corrupting your save:
1. -When quitting from playing, press the start button and select “Quit”, then yes.
2. -Let it sit at the main menu for 30 seconds, then hit the red button (B).
3. -Let it sit at this menu (the one that asks you to press start) for another 30 seconds, then hit your Xbox button to bring up the dashboard and exit to the dashboard.
4. -Now you can safely turn off your console.