i reverted to nougat this morningOkay i managed to fix the problem (somehow). All you have to do is just install fb & messenger that has another key other than official fb from PS.
https://xdaforums.com/android/apps-games/bullshified-version-facebook-okay-to-t3586318
Follow the 2nd post to sign apk with a test key. If u don't want to do that PM me. I will share the apk i made.
btw thank you