The recipe book reads that firework stars (small ball single color) are made with a dye and gunpowder, but when you check it, a couple of them aren't consistent. This is what happens when you try and make black or white firework stars:

Expected result: Put in gunpowder and black or white dye and get a firework star!

Bug: Put in gunpowder and either an ink sac or bone meal and get a firework star...

I wouldn't have reported this if cacao beans were part of it too (it would make it seem more intentional) but they aren't, a brown firework star uses brown dye like you'd expect.