Missing app icon in login page for iPhone (but present in iPad)

The WebAuth login page used to show my app icon by using v1 API, but it missed the app icon when using v2 API with this SDK for iPhone.
Like this

I am using the latest version of the SDK here.
It's weird that the app icon is always present on iPad with exactly the same code. Why??

My code snippet:
```
[DropboxClientsManager authorizeFromController: [UIApplication sharedApplication] controller: controller openURL: ^(NSURL *url) {
[self handleAuthenticationResult: controller url: url];
} browserAuth: NO];
```