Bug#781055: Mute button behaves oddly

[sacrificial-spam-address at horizon.com]

Package: linphone
Version: 3.6.1-2.4+b1
Architecture: i386

Pressing the mute button draws a red X on the button and audio is
muted.

After a minute or so, the red X disappears, but audio remains muted.

If I click again, the red X re-appears for another minute, then
disappears again.  The audio remains muted.

To un-mute audio, the user has to click once to make the X appear,
then again to make it disappear.

It's an annoying UI-out-of-sync-with-engine problem.