"False sense of privacy"
https://www.bleepingcomputer.com/news/security/meta-fixes-easily-bypassed-whatsapp-view-once-privacy-feature/
A privacy flaw in WhatsApp, an instant messenger with over 2 billion users worldwide, is being exploited by attackers to bypass the app's "View once" feature and view messages again.
Meta says that WhatsApp's "View once" feature (introduced three years ago) enables users to share photos, videos, and voice messages privately, seeing that the recipient shouldn't be able to forward, share, copy, or screenshot their messages because they will automatically disappear from chats after being opened once.