MSFT had a similar experience with HCL (I think it was them, one of the large Indian outsourcing firms in any case) when I was working on Vista. All fixes for bugs identified by static analyzers (PREfix/PREfast) were outsourced to contract programmers who had zero familiarity with the Windows source code. The “fixes” they sent back almost invariably introduced new bugs, and the whole back-and-forth process took much more time and effort (and presumably money) than just having the code owners fix the bugs in the first place.