The bug
It looks like sometimes when closing the world the following error is logged (by the "Sound engine" thread):
Stop: Invalid name parameter.
(In 21w17a it was logged by class dns
; com.mojang.blaze3d.audio.OpenAlUtil
)
Exact reproduction steps are unknown, and it is not known either whether this has any noticable effect.
@unknown has found this occurrence of the error in a log file from 1.14.4, so the error does not appear to be new.
I can confirm.