Hi! I'm using my modpack Lennbain (https://www.curseforge.com/minecraft/modpacks/lennbain, I am linking it because it's an easy-to-access way to see what other mods I'm using) which features Pretty Pipes v. 1.9.3. I have set up a storage system with Pretty Pipes but I can't seem to filter (using the Low Filter Module and the Filter Increase Modifier) non-stackable items at all.
This includes items such as enchanted books which are stackable in my modpack thanks to a different mod.

Edit: This is on a server, and as soon as I noticed that nonstackable items weren't filtering I tried to test stackable items and nothing at all went into the chest that I had set to filter the items into.
Edit again: everything works just fine in a singleplayer world.

I think the problem was with the server, not the mod.