We haven't changed *anything* that could be remotely related to the parking brakes. And as I've said, even if the *detection* of the parking brake in GSX didn't work, the worse it can cause, would have GSX issuing message about set/remove parking brakes at the wrong time, but NOT the ability to USE the parking brake in the airplane, that's just not possible, since GSX will ever, ever, try to operate the parking brake by itself.
So, whatever it was, and whatever the fix was, it couldn't be GSX and it couldn't be fixed by a GSX update.