Custom Rewrite Rules – query_vars issue

I have create the following function that is hooked on init action, in order to add my custom re-write rules:

public function customRewriteRules()
{
    add_rewrite_tag('%specialty%',  '([^/]+)',  'specialty=');
    add_rewrite_tag('%region%',     '([^/]+)',  'region=');
    add_rewrite_tag('%lngg%',       '([^/]+)',  'lngg=');
    add_rewrite_tag('%zpcd%',       '([^/]+)',  'zpcd=');
    add_rewrite_tag('%find%',       '([1])',    'find=');

    add_rewrite_rule(
        '^find/([^/]+)/([^/]+)/([^/]+)/?$',
        'index.php?find=1&specialty=$matches[1]&region=$matches[2]&s=$matches[3]',
        'top'
    );

    add_rewrite_rule(
        '^find/([^/]+)/([^/]+)/([^/]+)/page/([0-9]+)/?$',
        'index.php? find=1&specialty=$matches[1]&region=$matches[2]&s=$matches[3]&page=$matches[4]',
        'top'
    );

    add_rewrite_rule(
        '^find/([^/]+)/([^/]+)/([^/]+)/([^/]+)/([^/]+)/?$',
        'index.php?find=1&specialty=$matches[1]&region=$matches[2]&s=$matches[3]&lngg=$matches[4]&zpcd=$matches[5]',
        'top'
    );

    add_rewrite_rule(
        '^find/([^/]+)/([^/]+)/([^/]+)/([^/]+)/([^/]+)/page/([0-9]+)/?$',
        'index.php?find=1&specialty=$matches[1]&region=$matches[2]&s=$matches[3]&lngg=$matches[4]&zpcd=$matches[5]&page=$matches[6]',
        'top'
    );

    if(get_option('x_rewrite_added', 0) == 0)
    {
        update_option('x_rewrite_added', 1);
        flush_rewrite_rules();
    }
}

When I try the URL

https://www.mysite.com/find/someterm/someterm/somesearch/

I get the following query_vars

[query_vars] => Array
(
    [s] => none
    [region] => someterm
    [specialty] => someterm
)

and the following query_string

s=none&region=someterm&specialty=someterm

When I try the URL

https://www.mysite.com/find/someterm/someterm/somesearch/page/4

I get the following query_vars

[query_vars] => Array
(
    [s] => none
    [page] => 4
    [region] => someterm
    [specialty] => someterm
)

and the following query_string

s=none&page=4&region=someterm&specialty=someterm

But when I try to enter the following URL:

https://www.mysite.com/find/someterm/someterm/somesearch/someterm/someterm/

I am getting the following query_vars

[query_vars] => Array
(
    [s] => none
    [region] => someterm
    [specialty] => someterm
)

and the following query_string

s=none&region=someterm&specialty=someterm

as weill when I try the

https://www.mysite.com/find/someterm/someterm/somesearch/someterm/someterm/page/2

I am getting the following query_vars

[query_vars] => Array
(
    [s] => none
    [page] => 2
    [region] => someterm
    [specialty] => someterm
)

and the following query_string

s=none&page=2&region=someterm&specialty=someterm