The problem is when I make a search for the products and results count more than 20, pagination to the next page shows products from the first page. Results count is correct, but filtered products are not.
I use haystack simple backend for search.
In products catalog pagination works correct. I made some changes in oscar code and thought that it may effects to the search, but I checked clean installation of django-oscar with my database and get the same result.
After research I solved this problem with switching on solr search.
A little bit strange that I have to use old versions of solr and pysolr.
Solr 4.7.2 & pysolr 2.1.0 Newer versions give some errors but this two versions work as described in documentation.