I was having issues crafting the sequenced pulse generator because no stone type would work for it, and after looking through the source code I believe that I've determined the cause of the problem, the recipe calls for the tag "forge:stone", but because this is fabric, forge:stone likely does not exist, thus there is no acceptable item for the bottom row of the recipe.

I'm not a developer, so I don't know how to fix this myself, but I hope this provides insight if you have the time to pursue this issue.

Sincerely, Clancythecat.

I figured out how to edit jar files and changed "forge:stone" to "c:stone", works just fine now