I have seen this issue myself, but it has also appeared on the minecraft forum, posted by AzOutback.

The original post is found at this link:
http://www.minecraftforum.net/topic/1976915-villages-not-generating-in-13w37b/

In summary, given the following seed, 184631761013030455, and generating the world in 13w37a will give villages at the following locations:

A desert village at: 48, 368
A savanna village at: 16, 640
And a plains village at : 1152, -208

However, in 13w37b, those locations are empty of villages, even though the terrain at those coordinates is otherwise identical.

In fact, after extensive trials between 13w37a and 13w37b using AMIDST.exe, it appears that NO villages are being generated in 13w37b.