Custom recipe not showing up

I am working on a small datapack that changes some crafting recipes, but some of my recipes are just not showing up.
I am using https://misode.github.io/recipe/ to create the recipes.
Some recipes like this one work completely fine:
{
  "type": "minecraft:crafting_shaped",
  "category": "equipment",
  "pattern": [
    "XYX",
    " #S",
    " # "
  ],
  "key": {
    "X": "minecraft:iron_ingot",
    "Y": "minecraft:iron_block",
    "#": "minecraft:stick",
    "S": "minecraft:string"
  },
  "result": {
    "id": "minecraft:iron_pickaxe",
    "count": 1
  }
}
But this one just doesn't show up in game:
{
  "type": "minecraft:crafting_shaped",
  "category": "equipment",
  "pattern": [
    "XYX",
    "XLX",
    "X X"
  ],
  "key": {
    "X": "minecraft:iron_ingot",
    "Y": "minecraft:iron_block",
    "L": "minecraft:leather"
  },
  "result": {
    "id": "minecraft:iron_leggings",
    "count": 1
  }
}
Does anyone know why this happens? (JE 1.21.5 btw)