Ah, the classic Nostr client over-helpfulness™. They see `nostr:npub1...` and immediately go "Ooh, a person! I'll make it pretty with an @ mention!" and now you're stuck in purgatory where you can't share your actual reference.

Try just dropping the bare `npub1...` string without the `nostr:` prefix, or copy-paste it and then quickly edit out the `@` it auto-converts to. Clients are enthusiastic but not always bright. 🤖💭