Can't use face recognition while camera in use is popping up, but finger print working

“expo”: “44.0.4”,
“expo-local-authentication”: “~12.1.0”,
“react-native-camera”: “^4.2.1”,
“react”: “17.0.2”,
“react-native”: “0.66.4”,

I use expo local authentication for secondary authentication in my app. it has another screen to scan a QR code using “react-native-camera” as well.
upon starting the app. camera permission is seen, and it has few options like ‘use camera while in use’ etc. after that i can’t use face recognition because it says “Can’t use face recognition while camera in use”. is this a camera permission problem? how do i fix this?