Version
1.19.2 with 2.2.3
Describe the bug
When crafting using nbt smithing recipes with data merging, the tag base is erroneously added to the output.
Without adding "$": "base", NBT is not copied. When it's added, the stray tag is appended to the result.

To Reproduce

1. Use any smithing table recipe that merges NBT - e.g. this one
   netherite_chestplate_upgrade_sacrifice_sword.txt
2. The output will inlcude "$": "base" in the NBT tags

Expected behavior
The result item should not have any additional tag added - only the base NBT.

Observed this as well (more complex $ tags are included in the resulting NBT too), but the NBT appears to be functional regardless, it simply has some extra bogus data that is ignored. Not sure if this even needs a fix, as it doesn't break anything.