When testing the iOS 9 Beta with MobileIron, we discovered a very problematic change in the device's behavior.
When opening a Webclip, which refers to a websitre requesting a client certificate, there shows up a prompt to explicitly choose the client certificate to authenticate with.
The website requests a client certificate issued by a specific certificate authority, for instance CN=CA1/O=Acme (this is part of the TLS handshake).
The device does only have one client certificate issued by this CA (subprofile of a MDM profile).
The prompt to choose appears, even as the list does only contain this single client certificate.
In iOS 8 the device does automatically authenticate with the matching client certificate.
Therefore this feature is widely used for securing and authenticating access to corporate websites, and in regards of MobileIron for the Enterprise AppStore.
If this is no bug, and will remain in final iOS 9 release, we will be seeing immense user impact.
Please provide us with clarity on whether this is simply a bug or not.