Layered module is in conflict with posts per page

[moca.nu]

Hello,

 

I'm working on a website for one of my clients and I have a problem in the category page.

 

If I check filters in Layered Navigation everything it's ok.

http://elegance.moca.nu/magazin/21-cornise-tavan?id_category=21&n=20#/produs-cornisa_fara_model/price-39-189

But if I want to change posts per page all the filters are reset.

 

What's wrong?

 

Thanks,

Andrei M

Edited December 3, 2013 by moca.nu (see edit history)