[SOLVED] Subcategories not showing in a third level menu

I just tried to add a Wordpress menu instead of the atahualpa menu to my site.
I created some categories and assigned articles to them. Categories are organized on 3 levels: menus for the first 2 levels work good, that is, if I move the mouse over a top level category item, the drop down correctly shows. However, if I move the mouse over a second level category item with subitems, the menu shows but with only one element (the first one specified in the menu configuration).
I think it is a bug, how can I solve it?

EDIT
I just solved the problem upgrading from Atahualpa 3.5.3 to Atahualpa 3.6.4