Same issues here on a Startech dock - just updated to Monterey 12.1 last night, going to see if the issue still occurs.

@clayq - please let use know if it helped.

I just answered it myself. Upgraded to 12.1 Monterey MacOS and it doesn't change the behavior. Booting up with the Display Link attached works: sound can be directed successfully to Dell USB Audio. Disconnecting and reconnecting the Mac to the DisplayLink
will result in the sound not working through the DisplayLink.

Same problem, DisplayLink 1.6.0, Monterey 12.1 and on a 2019 Macbook Pro.

Same problem, DisplayLink 1.6.0, Monterey 12.1 and on a 2018 Macbook Pro.

Kate K from DisplayLink tech support got back to me suggesting I use Activity Monitor to quit "coreaudio". I don't have that as a process, but do have "coreaudiod". I forced that process to quit and it immediately started back up and the sound came through the DisplayLink audio jack just fine.

Interesting work-around, but not a final fix. Not sure if the fix is with MacOS or DisplayLink having to deal with the new MacOS.

I logged an issue via Apple's Feedback Assistant as well.

I am having the same problem with an M1 MBP 13".

The suggestion made by @g716 has been working as a quick fix for me as well.

I've got a D6000 dock and I've just upgraded to Monterey and my external audio output no longer works.

Killing the coreaudiod process 'fixes' the issue for me too although it's obviously far from ideal.

Here it stopped working even killing the process now. Nothing has changed, no updates recently. So weird...

I've got the same issue. Has anyone actually raised a support ticket for this as the DisplayLink team don't actively look at these forums?!