If you get variations across Fuji film types, it indicates that there is a problem with the relative speeds in those films. So it might be a film problem as well.
If it happens within one roll of film, then it could be a color temperature problem of the light source (daylight vs tungsten can cause this type of problem for example).
If it happens with one negative over several batches of paper, then it is a paper problem.
Of course, unless you do all of the variations, you cannot eliminate the possibility that it is a combination of all of the above.
I've seen batches of negatve materials out there with big variations in relative speeds (both paper and film), and the mfgrs just let it go and rely on the customer to rebalance their exposures. That is not good. The negatives that I have are stable in color balance over the 50+ the years worth of them that I have, and the print exposures are stable at about 50R for that same time period.
I use a lot of color paper, but rarely use Fuji.