My first guess for that would be the text-to-speech module? 1. Start Kontact --> see pulseaudio draw cpu power 2. Close Kontact --> see pulseaudio cpu dropping after 2-5 sec. Can anybody confirm that? I am using a Tuxedo Infinity Book. See also https://bugzilla.suse.com/show_bug.cgi?id=1091752.
Frederik, does that sound familiar ? (the openSUSE link has a few more comments)