After using a banner pattern on a banner inside a loom, the banner pattern is not consumed, therefore letting you use it unlimited times.
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Special banner patterns (Oxeye Daisy, Creeper Skull, Wither Skeleton Skull, Enchanted Golden Apple) can now be crafted. These patterns don't consume the pattern item when used in the Loom
https://www.minecraft.net/en-us/article/minecraft-snapshot-18w43a
Works as intended