Webview orientation / rotation issue with Facebook Unity SDK

Facebook Unity SDK internet browser login stuck in portrait mode even though my game is in landscape. All the code is in the native library and I don't have access to modify it.

The issue seems to be fixed in Facebook iOS SDK v3.18, but not yet in Unity SDK v6.1 beta https://developers.facebook.com/docs/ios/change-log-3.x#3_18

Any help would be greatly appreciated or could be fixed in the next version if anyone on Facebook is reading this? Thanks you

Also Facebook app login app doesn't work on iOS and it always uses webview by default. However, it seems to work fine on Android.