I know there is nothing wrong with the fuji paper.

If you have zeroed out the yellow, simply increase equal amounts of cyan and green filter and you will in effect add yellow

yellow is the combination of equal amounts of green and red. with three filters C, Y, M on your dichroic head you can make any combination work.

It may be time to inspect the dichroics in your enlarger?

With millions of feet of paper being manufactured by fuji I seriously doubt it is a paper problem.

Bulb colour tempature could also be a problem here , as they are ready to go they will suddenly change Kelvin temp.

When printing various emulsions from Kodak and Ilford and Fuji, we are constantly changing our exposure values for the different stocks.