I have always had some mottle, no matter what I do, both on Fuji CA and Supra Endura. And yes, it seems to vary. If the mottle is very excess, it's probably just the good old problem of too restrained development, causing also the "cyan highlights" problem. It is mitigated by lowering the bromide level.
Dektol as-is, I got cyan highlights on Kodak Supra Endura, and white highlights but ugly greenish-grey shadows on Fuji CA. For Kodak, the solution was to lower the bromide level (scratch mix, as you cannot remove it from a solution...), for Fuji, it was adding hypo -- the bromide seemed fine.
I have had equally good results with both papers (on average), but the optimum bromide level in first developer is very different; IIRC, something around 0.2 g/l for Endura and 1 g/l for Fuji... Also if you add a bit hypo or SCN to FD, these levels vary between papers -- Fuji NEEDED some hypo to get good blacks, and, OTOH, managed quite high levels of hypo without burning the highlights, whereas Supra Endura worked best without hypo or with 1/10 of the amount of Fuji, to give a careful boost on highlights. Hypo levels suitable for Fuji caused Supra Endura to go very wild in contrast, really a posterising effect, which I will definitely keep in my "artistic toolbox" if ever needed.
Sometimes I had better results with Supra Endura, sometimes with Fuji CA! Go figure. This might need much more testing .