Periodically, while playing the game, the sounds just stops working. I have tested this in 1.12.2 and have not seen this issue in that version. When this happens, the "Sound" value in the debug screen sits at 247/247 + 0/8 and won't move. I have to go into the pause menu, and play around with the controls in the sounds options menu. When I do that, the "Sounds" value suddenly goes down to 0/247 + 0/8.
Also, this seems to be tied to certain Z values; as I move north and south, this number creeps up "1... 20.... 40... 80... 127... 178... 237..." then silence. I have to pause the game, play around with the controls in the sound menu to get it back.
Is this still an issue in the most recent versions (currently that is 1.16.3, or the latest pre-release 1.16.4-pre1) of Minecraft? If so, please update the affected versions and help us keeping this ticket updated from time to time. If you are the owner/reporter of this ticket, you can modify the affected version(s) yourself.