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 Desktop Packages, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1850646 Title: Sound output device switched on DP/MST connect Status in pulseaudio package in Ubuntu: Invalid Bug description: 1. Starting with sound output set to line-out with DP/MST/HDMI monitor connected. 2. Disconnect monitor. Sound output remains on line-out. Music continues playing etc. 3. Re-connect monitor. Music/sound stops being produced. Sound output device is switched to HDMI/Display Port 6 device. Sound output device should remain on user-selected device unless user interactively changes the output device. Or add configurable option for "sound output device auto switching". ProblemType: Bug DistroRelease: Ubuntu 19.10 Package: gnome-shell 3.34.1-1ubuntu1 Uname: Linux 5.3.7-050307-generic x86_64 ApportVersion: 2.20.11-0ubuntu8 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Wed Oct 30 10:14:02 2019 DisplayManager: gdm3 InstallationDate: Installed on 2018-12-04 (329 days ago) InstallationMedia: Ubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.3) RelatedPackageVersions: mutter-common 3.34.1-1ubuntu1 SourcePackage: gnome-shell UpgradeStatus: Upgraded to eoan on 2019-10-23 (7 days ago) mtime.conffile..etc.apport.crashdb.conf: 2019-01-08T10:59:11.363686 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1850646/+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