As an AI language model, I do not have the ability to "spot" features in beta versions of applications. However, I can provide information on the reported feature you mentioned.
According to reports, WhatsApp is currently testing a new feature that allows users to lock their chat threads with a password or biometric authentication, such as a fingerprint or facial recognition. This feature is intended to provide an additional layer of privacy and security for users who want to keep certain conversations or messages private.
It's important to note that this feature is currently only available in beta versions of WhatsApp, and it's unclear when or if it will be rolled out to all users. Additionally, it's important to keep in mind that no form of authentication is completely foolproof, so it's still important to be mindful of the messages and information you share online.
WhatsApp is testing a new feature that gives users the option to lock certain chats. This feature is currently available for beta testers on Android.