Oops, didn't know the file comment was an actual comment. Anyways, no crash, I simply noticed the log entries after exiting my session and was curious and searched the tracker and then found this bug entry. Just thought I would share my experience.
I can confirm this message is occurring in vanilla 13w19a. I just closed my game after playing for about an hour and saw this message in the new launcher window I didn't close when I started. It occurred about 20 times near the start of my game. All I did during the game was dig a fort, place a furnace and used it, placed some chests and used them, and made a farm. I can't recall what I was doing at the exact time the messages were spammed though. These messages are the only ones out of the ordinary inbetween the saving messages from pausing the game. It's possible it was the furnace I used and this message was when a fuel was still burning without items.
I still think the fact that Witches are spawning in and around the temples that spawn in swamps is a related, but separate bug. Because of the temples spawning everywhere, they may be intertwined with Witch spawns somehow when they appear in swamps.
Two screenshots with seed in the chatbox and F3 stats showing. I am using two mods, BetterFonts and OptiFine, but neither should mess with world generation at all. This temple had FOUR witches (second shot only shows three, fourth was inside).
@Shawn Cheever
That is the current workaround. The sound corruption occurs when random music attempts to play. Turn off the music and everything else keeps playing just fine.