I was able to see something similar on the desktop, and came up with a patch to fix it. Can you test it and see if it resolves your problem as well?
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to pulseaudio in Ubuntu. https://bugs.launchpad.net/bugs/1289515 Title: Sound volume resets after making a call Status in “pulseaudio” package in Ubuntu: Incomplete Bug description: 1. mute your phone 2. dial a number and ensure the call is picked 3. end the call What happens: The sound volume is set to full and the phone unmutes What should happen: Ending the call should not effect the sound volume setting. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: telephony-service 0.1+14.04.20140303-0ubuntu1 Uname: Linux 3.4.0-5-mako armv7l ApportVersion: 2.13.2-0ubuntu5 Architecture: armhf Date: Fri Mar 7 23:26:43 2014 InstallationDate: Installed on 2014-03-07 (0 days ago) InstallationMedia: Ubuntu Trusty Tahr (development branch) - armhf (20140307.2) ProcEnviron: TERM=linux PATH=(custom, no user) SourcePackage: telephony-service UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1289515/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp