It only affects one user and their MultiFactor account works happily when challenged from a Windows Moble, Android or Computer.
The 2FA challenge happens when enrolling the iOS device in Intune and 2FA comes before federation join and Intune enrolment. The user is presented with the GRA login and inputs their network credentials, the system appears to try and authenticate but no challenge is received and no error is returned, just the GRA login again unpopulated.
Again the MultiFactor account works clean on any other platform and we have tried multiple other iOS devices AND passed 2FA challenge using another account on the same iOS devices.
Anyone seen this and have a direction as to where to look to fix this?