WB what does C1?

Hi, my cam. Fuji X-Pro2 is set to K 5.600, 0, 0 (RAW). But C1 shows 5.343, -0,1.

There is no auto set to WB or elsewhere (I believe). Exiftool shows as camera settings.

Please, what happens here? It´s not very importend but I would like to know. Thx. lars

It is C1-21, Mac