Ken,
I'm not a medium format digital guy, but I'll try two answers out on you anyway.
As for the cause of the problem, to my eye it's a clear case of weird, very hard light coming off a window in the tall building in back. I don't see it as a camera problem.
As for a solution, I tried the Color Replacement Brush in Photoshop. (Set to Color, Contiguous, Tolerance in range of 20-30.) I've attached my result. I made sure not to spend more than five minutes on it--I didn't want to recommend a solution that would be unrealistic, and I'm lazy. Since you'll be working on bigger and better files, I'm sure your results will be better than mine.
For what it's worth...
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