Zap validation is also expensive (network requests and computation) and multi-step and also stateful.

If I change my lud, all previous ZAPs now technically should fail validation, unless you change it back. You either need a profile/lud snapshot at the zap time, or to validate zaps instantly (read: race condition and impossible in a decentralised network) and record that outside of Nostr, to the query later.

Zaps are awesome. But they aren’t trustworthy or polished in many ways. Hopefully we can iterate.