Reference: MC-268833
Expected behaviour:

You should be able to use the same data path for '/data get' and '/data modify' at all times.

What happens instead:

When modifying a component on an item with '/data modify', you can use the component name without the "minecraft:" part, but only if that component is not already present. If it is already present, or if you're using /data get, this will not work.

How to reproduce:

• Put a sword in a chest and run the following command:
  • /data modify block x y z Items[0].components.enchantments.levels."minecraft:sharpness" set value 1
  • => Notice how this worked, despite using enchantments instead of "minecraft:enchantments"
• Try the data modification again, this time with sharpness 2
  • => Notice how this didn't work, as it now requires "minecraft:enchantments"
• Also try the following command
  • /data get block x y z Items[0].components.enchantments.levels."minecraft:sharpness"
  • => Notice how this also doesn't work