I've same issue in v18.0.2. But i'm using AppDelegate.
My issue is only user authorize open Facebook App, user authorize in WebView is fine.
I research and tried a lot but didn't found any solution. Function func application(... open url: URL, ...) -> Bool in AppDelegate recieved callback and i call return with this return ApplicationDelegate.shared.application(app, open: url, options: options), but the webview still there