Discovered on Ubuntu 20.04, kernel 5.4.0-33-generic. Not tested elsewhere, but reproducible every time on my machine for final versions back to 1.13.2.
Exact steps to recreate:
Select desired audio output in Settings > Sound > Output Device
Start Minecraft
Confirm that buttons and music play through that audio device
While the game is still running, change Settings > Sound > Output Device to an alternative one
Confirm Minecraft is still playing audio through the first device
Let me know if it's just my machine, or if there really is something funky going on somewhere.
Environment
Software used:
Ubuntu 20.04, kernel 5.4.0-33-generic
Bundled Java Runtime (11.0.7 64-bit)
Hardware used:
Blue Yeti Microphone (As primary audio output device with headphones)
NVIDIA GeForce GTX 980 Ti (As alternate output device over HDMI)
Linked issues
Comments 2
Correct, MC-44055.
Pretty sure that this is a duplicate of a bug that has been resolved as 'Won't Fix'.