Tried running through with that, but it still doesn't seem to work. I tried messing with my chalk block recipe and it comes across with the same issues. It functions normally when I'm using the modded items, but as soon as I add a single minecraft base item it stops.
Edit: Figured I should place this to make sure I'm not being silly and messing up, this is how I did the metadata, I may have gotten it wrong.
"item": "minecraft:dye", "data":15
Edit 2: I've found out that for some reason leaving any row blank or not having it is causing it to also not show up for some reason. I'm really baffled by what's going on.
Edit 3: I figured out the problem, I forgot a comma during the key definitions. Whoops.