Would u describe how you using them for rooting? What method you was using? Do you monitor temperature?
My house was roof leak with high moisture of 60% yearly, Sun is blocked by new tall house, no gas heater, I tried rooting with Sandwich bag/wet towel method, pure perlite, Co coir, Pro-Mix HP, 10% beach bath, at 75F warm spot, it has 100% fail due to mold.
I used same method outdoor non-direct sun area with 50 to 75% success due to un-regulated low temperature, I think that sunlight UV kill molds in air, Co coir is the best for me so far.
So far, I have very bad experience growing fig trees, due to low rooting successful rate, I end up buying couple big nursery fig trees last year and planted them in ground, I got few figs first year, this winter, I am at Zone 8B, 50% of them freezing dead to ground, new sprouts from suckers now, It will be no fig again another year, too many red tapes, E.X, hard to get cutting in Canada, cool summer, FMV mites(I find white spots on my potted fig trees now), I cut all resource for this project.