I too am very interested in hearing any about progress on this issue?
We recently migrated a lot of traffic from our old authentication system, and are experiencing the same invalid state error, spread across a host of iOS devices (Both iPhone and iPads) with no appearent pattern in the affected iOS version.
We also released a web based client, which is used on both iOS, Windows and other platforms, where the error has not been reported, so the error seems to be localized to the iOS apps.