Minecraft Version: 1.15.2
forge-31.2.22
fl-3.3.0.jar
flux-4.16.1.jar
(The issue also happened with the older versions that came with Beyond Limits 1.15, but I updated everything before submitting)

If I just use coal in the flux generator it consumes coal with the progress bar in the middle going all the way up, then consumes another coal and starts over. 40rf/t

If I use redstone as a catalyst it doesn't consume any coal or redstone after the first one of each and the progress bar never moves. 80rf/t without using any fuel.