I had the opportunity to test an IQ180 back for five days in April and noted some inconsistency with the automatic white balance, i.e. pictures taken a few seconds apart were yielding significantly different color temperatures.
The PhaseOne partner here lent me another back, IQ180 as well, today.
I attach two pictures taken two minutes apart in daylight, WB set on auto. The first picture has a WB of 4,850 and the second one of 2,800. I know the first one is not in focus: took me a few seconds to realize that focus activation had been set to the AEL button ;-)
I then took some pictures of my wife in my studio, with the lighting coming from ProFoto lights. The inconsistencies are not that significant, but they are clearly visible.
I know that I can take steps to fix this in Capture One, but I would anyway be interested to know whether other people have met the same issue and whether there is some explanation for this.