Switching on connect is an intentional design choice for Ubuntu. If you would like to disable it then please just comment out this line:
load-module module-switch-on-connect in /etc/pulse/default.pa So this isn't a bug, but it does seem to overlap with bug 1847570 so please see that too. ** Package changed: gnome-shell (Ubuntu) => pulseaudio (Ubuntu) ** Changed in: pulseaudio (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1850646 Title: Sound output device switched on DP/MST connect To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1850646/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs