It's one of Amethysts many rough edges. I can zap your profile, but get an error when zapping your posts. It's not just you, that software behavior exists based on the wallet, it seems.

Some wallets I can zap notes, others not, but if I want to take the time to visit their profile, generate an invoice, enter the amount, then I can zap. 🤷🏻‍♂️