Stereo Downmix not working in Jellyfin media player

[motolly3]

For what it's worth I noticed that suddenly anything that needed to be down-mixed to stereo was barely audible. For me at least down mixing is a purely client-side operation so long as the player can make sense of the supplied audio.

Changing audio output from "default" to "Pipewire" and changing audio channels from stereo to "auto" then restarting playback seems to have solved the issue.