As per https://github.com/expo/expo/issues/4701, Facebook login on iOS doesn’t work much of the time (some devices on iOS 13 are succesfully logging in…). It always return “type: cancel” even though the authentication succeeded.
Edit: Have you tried behaviour: 'web' ? This works for us. However, it prompts the user to enter his facebook credentials, which makes the login experience worse - not every user remembers his credentials
Yes, behaviour: ‘web’ works, but as you said it’s so slow that way that the goal of putting a “Login with Facebook” button disappear completely. And as you said, a lot of people don’t even remember their credentials…