Comment 1 for bug 1712858

It appears you are missing a few months of updates. In particular, missing a bug fix update:
  pulseaudio 1:8.0-0ubuntu3.3

Please update your system using these commands:
  sudo apt update
  sudo apt full-upgrade

After you have updated and rebooted, check if the problem continues. If the problem persists then please run this command to send more information:
  apport-collect 1712858