MC Version 1.15.2
Mod version: DarkUtilities-1.15.2-3.1.8
Mod Pack : Vallhelsia 2
Forge: 31.2.43

I cant seem to invert these filters. I right click them once placed with open hand nothing, i sneak right click and also get nothing. I tried to put them into a crafting table (guess thats how they were inverted once upon a time) and they dont work either. I also dont see an iverted item in the JEI.

Am I doing somthing wrong?

Ok found out what up. Did a bunch of testing but then I noticed I had a shield equipped vs the test runs where I found it worked.....
so if you have a shield equipped, Minecraft version or modded otherwise, you cant swap it.