APNS banner doesn't appear on home screen while using send_multiple

[MrCsabaToth]

Not the same as #181 because send_multiple works in my case if the application on the iOS device is in the foreground. However there's no banner seems to be stacked on the home screen (as usual for other applications) when my application is in the background or stopped so the user would see it during the next unlock.

Strangely the banner seems to show up on the home screen if I avoid using send_multiple.