Filter not showing on every page

Hi,

i have issue that product filter widget appears only on specific pages of my variable products. I have menu that looks like this:

Shop
Parent Category
Child category 1
Child category 2
Child category 3

Widget filter for size appears on Shop page, Parent Category and Child category 3, but it doesnt work on on Child 1 or 2.

I checked my variable products on Child 1 and 2 category pages, and they are ok. When I try to filter products from Shop or Parent Category page, I get them.

When I go directly to Child category 1 or 2 page, there is no widget filter for attribute.

Thanks

The page I need help with: [log in to see the link]