These biometric security measures were introduced earlier this year, but appear to be relatively easy to ignore.
Reddit user "de_X_ter" outlines the steps required to bypass Apple's biometric security locks in a post on the Apple subreddit:
Navigate to the iOS Share Sheet
Select WhatsApp
While moving to the next screen, no FaceID or Touch ID verification takes place
Exit to the iOS Home Screen
Open WhatsApp
"If in some cases, it [the third step] asks for FaceID or Touch ID verification, just cancel it and try clicking on the WhatsApp icon in the iOS Share Sheet again," the user said.
"This bug does not occur if ‘Immediately' has been set inside WhatsApp Screen Lock Settings," the user added.
Apple responded by saying it is working on fixing this security flaw.
"We are aware of the issue and a fix will be available shortly. In the meantime, we recommend that people set the screen lock option to ‘immediately,'" said Apple.