I make an video call from a CIsco IP 9971 to an Cisco Cius. Call established, both can speak an hear. At the 9971 I can see the video, at the Cius the video is shortly appearing and the going down. At display message appears like this: "phone process phone.cisco.com unexpected ended. Please try it again."
But the call is still established. Both can hear and speak and at the 9971 I still see the video from Cius camera. CUCM is a 8.6.2