The recipe for 1337Fleece has some errors:

{
  "type": "crafting_shapeless",
  "ingredients": [
	{
	  "tag": "bwplus:fleece"
	},
	{
		"tag": "bwplus:fleece"
	},
	{
		"tag": "bwplus:fleece"
	},
	{
		"tag": "bwplus:fleece"
	},
	{
		"tag": "bwplus:fleece"
	},
	{
		"tag": "bwplus:fleece"
	},
	{
		"tag": "bwplus:fleece"
	},
	{
		"tag": "bwplus:fleece"
	},
	{
		"tag": "bwplus:fleece"
	}
  ],
  "result": {
	"item": "bwplus:rgb_witch_wool",
	"count": 9
  }
}

in game it appears as:

I believe to fix this the tags should be replaced by proper item IDs or proper tags for witch wool items which is what 1337Fleece derives from.

to clarify on the title, because it thinks it can craft 1337Fleece from nothing, it tries to craft 1337Fleece for every in-game crafting recipe.

so far the best solution to this is to remove the recipe using something like kubejs.

https://discord.gg/hpDv9FQJAS

Discord for the mod is here. See if you can raise the issue a bit.

Any update on this issue?

An easier solution is to just populate this missing tag yourself with a datapack. I have done this for my modpack and can upload it to share if BWPlus isn’t planning on fixing it themselves.