In the process of getting to know my new 16/1.4 I have unearthed what appears to be a bug in the X-Pro 3.
These shots were taken at f1.4 and are of a cushion...which appears to be covered in dog hair
The first shot is taken from a distance of about 20-30cm - so well outside minimum focus distance. As you can see the plane of focus is very thin and the cushion is BLUE:
The second shot is taken close to but not at the minimum focus distance. At some point between the previous shot and this one the shot turned black and white in the viewfinder and is black and white to all intents when viewed in C1.
The settings are exactly the same for each shot...the only thing that changed was the focus distance.
These two shots were both on Auto white balance, however the same thing happens on Daylight white balance.
The same thing does not happen when focusing on a non-backlit reddish surface - it retains its colour to close to minimum focus distance.
It sort of feels like a bug but I may be missing something.
Postscript: On further testing this appears when almost the whole picture is of the blue fabric. If the picture contains enough background/other colours then it remains blue, so long as the shutter button remains depressed in S mode you can then move into a situation where the whole picture is blue and it will remain blue. A red cushion of the same material in the same position does not exhibit the problem.