Market walker doesn't work properly.

When market just placed, trader successfully gives food to all people, and homes grow. But then, it's starts to give food only to nearest homes, and other don't get any food. After that homes devolve.
Example after some time:
http://i.imgur.com/XJooXal.png
After placing, all homes are evolved to Insulas, but then devolved, after trader stopped to give them food.