Also curious about how the problem exhibits itself. I assume the two shutters aren't coordinating correctly?
Is there any reason to use the shutter in an LS lens other than when using flash? Currently in mirror up mode, the FP shutter still fires nearly identically when using the lens shutter so the camera is still bouncing around.
Any chance they were trying to make this work "correctly", by closing the lens shutter and opening the FP shutter when in mirror up mode, and it just didn't work? (I know- wishful thinking, they would have put this in the release notes.)