Strange behavior in flow for Facebook login in iOS 11

Question

I am currently working with iOS 11 beta (Xcode 9 beta 4) in order to integrate new features to my app. I have Facebook login (Facebook graphAPI version 2.8, sdkVersion 4.17.0).

Apple removed social accounts in iOS 11, and now, when testing my app, I faced strange behavior in flow of Facebook Login.

How it was working earlier: User pressed on button “Login with Facebook”, and if he has Facebook account on device he automatically went to the next screen. If he does not have account - opened Safari and asked user to login to Facebook or opened Facebook app, and redirect user to my application.

What weird behavior I have on my device (iPhone 5s) with iOS 11:

1. I press button “Login with Facebook”.
2. Opens Safari with options: Login with the Facebook app, Login with phone or mail.
3. I press Login with Facebook app.
4. Appear alert: open in Facebook.
5. I press open.
6. Opens Facebook app. At this moment nothing happens.
7. So I have to press button back to my app. I see Safari screen and repeat steps 2-5.
8. After that I see confirm login screen: You previously logged in with Facebook. I press button “continue”.
9. I am redirected back to my app after login and go to next screen.

Some times after step 6 I go to step 8 and 9. This happens randomly. I don’t understand why.

I tested on other devices with iOS 10.3, 10.2 (iPhone 6 Plus, iPhone 7) and with FBSDKLoginBehaviorNative (both with Facebook account in settings and without Facebook account in settings). On other devices, when I press button “Login with Facebook” I see Safari with confirm login screen (as described in step 8).

This is code for Facebook login, that I use:

-(void)loginWithFacebook
{
FBSDKLoginManager *loginManager = [[FBSDKLoginManager alloc] init];
 loginManager.loginBehavior = FBSDKLoginBehaviorSystemAccount;
[loginManager logInWithReadPermissions: @[ @"email", @"user_birthday", @"user_friends" ]  fromViewController: self handler: ^(FBSDKLoginManagerLoginResult *result, NSError *error) 
{
            if(error == nil)
            {
               //  here I get user data and go to next screen
            }
            else
            {
                //here I show error alert to user
            }
        }];
    }
}

In AppDelegate:

    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
//…
[[FBSDKApplicationDelegate sharedInstance] application: application didFinishLaunchingWithOptions: launchOptions];
//…
}

- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation
{
return [[FBSDKApplicationDelegate sharedInstance] application: application
                                                                        openURL: url
                                                                  sourceApplication: sourceApplication
                                                                          annotation: annotation];
}

- (BOOL)application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary *)options
{
return [[FBSDKApplicationDelegate sharedInstance] application:app openURL:url options: options];
}

So, my question is, have you faced with this behavior on iOS 11? What should I do (if I can do something) to fix it? After new release of iOS 11 user have to go though all this steps to make Facebook login?

Thank you for your reply and your help.