I noticed I could not name my Netherite pants at the Anvil and thought maybe it was a feature that you couldn't name items once they had Netherite. I tried to name my new dog with a name tag and it also wouldn't work. That's when I realized it was a potential bug. This did not happen until after the most recent update so I can only assume there is a connection. Please fix this if it is a bug. Butter the dog will thank you!