Finally, I’ve found an answer. Not sure if it’s specific in my case or it’s a general WP issue but default value for posts per page set up in WP admin (General > Reading > Maximum number of posts per page) should be less than value for posts_per_page parameter for custom query. In my case, I’ve changed in WP options value to 3 and for other page changed this to 5 and all working fine now!
