Players on both the 360 and PC platforms (PS3 seems to also now be available appears to not be available for download yet) are reporting bug issues with the latest patch and download necessary to play as Borderlands 2's latest character, Gaige.
According to threads on both the official Gearbox forums and Giant Bomb's, some players are experiencing a loss of their Badass rank, which was actually a problem players had even before this update. Whether this is a return of the bug, or simply previously unaffected players experiencing the bug for the first time isn't clear.
Others are reporting more extensive issues, like the loss of character skins, golden keys, and full saves.
We've tried replicating the problem on our end on the Xbox 360, but everything appears in order. Let us know if you have problems in the discussions below, and maybe hold off on downloading the patch and Mechromancer until this clears up.
Update: Mike Fahey says his progress on the PC version seems just fine, too.
We've reached out to 2K on the matter and will update if we hear back.
Update: 2K responded to Kotaku with this official statement, clarifying that the patch/Mechromancer download that released today have nothing to do with the bugs in question:
2K and Gearbox have been working steadily to fix a bug reported to us by fans that resets Badass Rank, and while this bug has only been affecting a very small number of players worldwide and does not affect the ability to play Borderlands 2, addressing this issue is still very important to us. We ask that players who have experienced this issue to email us at profiles@gearboxsoftware.com with as many details as possible to help us gather additional information so that we can squash this reported bug.
Coincidentally, a patch was released today and the fifth playable character class, Gaige the Mechromancer, became available for purchase and download today across PlayStation 3, Xbox 360 and PC via Steam. The patch and the Mechromancer downloadable character class are in no way related to the Badass Rank issue, and fans can feel confident when downloading either item. A further compatibility update will follow in the coming days to address connectivity issues between those who have the Mechromancer and those who do not. Full release notes for today's patch can be read here: Xbox 360, PS3, PC.