@Henk Langeveld Thanks for that workaround!
I understand that the fix will be in a future version, however I played for nearly 3 hours this morning without any sound issues (13w21a). I did turn "Music" to "Off" during gameplay so that may or may not have affected it; sounds still worked after 3 hours.
I can confirm that this issue is happening on my end also. Just recently upgraded to snapshot 13w21a.
Confirmed still in 13w21a.