You may be experiencing a bug in the underlying sound server PulseAudio (or its configuration in a given distribution) used by many distributions including Debian, Ubuntu, and many other distributions derived from these.
To fix the issue open a terminal and run the following commands:
sudo nano /etc/pulse/default.pa
Find the line that reads "load-module module-switch-on-port-available" and comment it out by adding a # sign in front like this:
#load-module module-switch-on-port-available
Hold your ctrl key down and while doing so tap the x key. You will see a message asking you if you would like to save. Hit the y key. You will then be prompted for a filename. Simply hit the enter key to accept the default name.
Then run the below commands to restart the PulseAudio sound server and test the resulting change:
pulseaudio --kill; pulseaudio --start
systemctl suspend
Assuming your audio resume issue was the result of a bug or configuration issue upon resume your audio will probably come back up without a problem. Open a media file or visit a web site with video/audio content and hit play to test.