Problem with pagination when paged=2

UPDATE:
I was busy digging these days without any luck.
I managed to intercept 404 error using the following code:

function log_404_error() {
    if( is_404() )
    {
        global $wp_query;
        update_option( 'last404error', json_encode($wp_query->query) );
    }
}
add_action( 'template_redirect', 'log_404_error' );

Then I read/get last404error in 404.php using URL:
https://www.mydomain.com/en/bookstore/page/3
404.php displays $wp_query->query parameters as follows:
{“paged”:”3″,”post_type”:”bookstore”,”lang”:”en”}
Any idea?