Unless they've changed something, I know at least at the very beginning Zelle had no fraud protection.

https://techcrunch.com/2018/02/16/zelle-users-are-finding-ou...

It appears they still have issues with (more advanced forms of) fraud:

https://thecyberexpress.com/zelle-lawsuit-2025-scam-hit-us-f... (this page won't stop reloading, but I think it's my adblock configuration) https://www.morningstar.com/news/marketwatch/20241221198/mor...