Skype sounds lower the volume of other applications

[mf2]

I'm using pulseaudio, skype and the music player clementine together.
When I receive a chat message via skype, the volume of clementine gets lowered as long as the notification sound of skype is playing.

I would like to disable this behaviour and tried:

• Disabling the automatic mixer control of skype
  
• Disabling "module-intended-roles" and "module-role-cork" in /etc/pulse/default.pa
  
• Using different versions of pulseaudio.
  

Well, nothing works. Disabling "module-role-cork" at least keeps the volume of applications like totem and vlc up, but clementine still gets lowered.

Searching everywhere in the internet brought nothing; I've tried google, arch/gentoo docs, the pulseaudio docs, etc.
Does somebody here has an idea?

Edit: Well, it seems that since a reboot the problem does not occur anymore. But maybe somebody knows a config setting or something else to ensure that this won't happen again