Minecraft 14w06a, Minecraft 14w06b, Minecraft 14w07a, Minecraft 14w08a
Java 7 Update 51, HD5450 card, Windows 7 Professional
Sound chops up when you are walking left to right. Only affects 14w06.
1. Start up 14w06b/a
2. Open a world
3. Walk with the right and left keys. The sound of whatever block you are walking on will be distorted.
Just for notice, I included a short video too in the attachments.
[EDIT: Only works for "soft blocks", which creates sand/grass sounds when being walked on.]
[EDIT: It actually works for most blocks, it's hard to hear the sound chopping on other blocks "eg. stone" sometimes.]