wordpress 3.6.1, feedwordpress Version 2013.050 , default 2013 theme. no other plugins. If i click on a category, wordpress indicate that there is not post in the category. The same pb appears in the admin section when you try to filter posts on categories.
De-activating feedwordpress make the category pages works again.
I found that "Turning ON Optimize "IN clauses" in the performance settings." solve the problem but i don't understand why.
Does someone have any idea about that ?