I have an issue where the call control buttons disappear when receiving a PSTN call to a response group. We are running Lync 2013 servers with the latest patches (apparently not the January ones), but using the Skype for business client (ver 15.0.4779.1001). When a call comes in to the response group and the agent answers it you see the call control button flash on the call window, and then it disappears. We can get the call control back by clicking on the "Speaker View" button on the menu bar of the active call. As well, users can still transfer calls by using the keyboard short cut, but some users here prefer the button. If we change the UI back to the Lync 2013 client the call control returns.
Any help with this would be greatly appreciated.
Thanks
Troy