Window favicon is 'corrupt' on Linux

The Minecraft window favicon appears 'corrupted' on Linux platforms - i.e. the crafting table icon is scrambled beyond a certain point.

I've tested this on Debian using both the GNOME and XFCE desktop environments, and Fedora using GNOME. Each shows the same bug, but with a slightly different corruption for each.

The attached image shows how it appears on a Debian computer running XFCE 4.8.

And yes, I have tested it using Java 7 instead of 6 - same problem.