FastCGI issue on wordpress multisite

Hi, i have FastCGI enabled and its working perfectly on my main site. but for my other sites which is in sub directory multisite setup, FastCGI is caching even the admin area too. i dont understand why FasctCGI is not bypassing sub-directory sites admin area when cache bypass is working for main sites admin area. i have opcache enabled as well. is that might be any issue here?

here is the response header from post page

Request URL:http://mysite.com/site2/wp-admin/edit.php
Request Method:GET
Status Code:200 OK
Remote Address:139.162.171.19:80
Referrer Policy:no-referrer-when-downgrade

Cache-Control:no-cache, must-revalidate, max-age=0
Connection:keep-alive
Content-Encoding:gzip
Content-Type:text/html; charset=UTF-8
Date:Tue, 28 Mar 2017 16:17:56 GMT
Expires:Wed, 11 Jan 1984 05:00:00 GMT
Server:nginx/1.10.3
Transfer-Encoding:chunked
Vary:Accept-Encoding
X-Cache:HIT
X-Frame-Options:SAMEORIGIN

and these are my FastCGI config

fastcgi_cache_path /var/run/cache levels=1:2 keys_zone=MYAPP:100m inactive=60m;
fastcgi_cache_key "$scheme$request_method$host$request_uri";
add_header X-Cache $upstream_cache_status;
fastcgi_ignore_headers Cache-Control Expires Set-Cookie;

        #Cache everything by default
        set $no_cache 0;

        #Don't cache POST requests
        if ($request_method = POST) {
                set $no_cache 1;
        }

        #Don't cache if the URL contains a query string
        if ($query_string != "") {
                set $no_cache 1;
        }

        #Don't cache the following URLs
        if ($request_uri ~* "/wp-admin/|/xmlrpc.php|wp-.*.php|/feed/|index.php|sitemap(_index)?.xml") {
                set $no_cache 1;
        }

        #Don't cache if there is a cookie called PHPSESSID
        if ($http_cookie ~* "comment_author|wordpress_[a-f0-9]+|wp-postpass|wordpress_no_cache|wordpress_logged_in") {
                set $no_cache 1;
        }

        location / {
                try_files $uri $uri/ /index.php$is_args$args;
                # try_files $uri $uri/ /index.html;
                # try_files $uri $uri/ =404;
        }

        location ~ \.php$ {
                fastcgi_split_path_info ^(.+\.php)(/.+)$;
                include snippets/fastcgi-php.conf;
                fastcgi_pass unix:/run/php/php7.0-fpm.sock;
                include fastcgi_params;
                fastcgi_param REQUEST_METHOD $request_method;
                fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
                fastcgi_cache MYAPP;
                fastcgi_cache_valid 200 60m;
                fastcgi_cache_bypass $no_cache;
                fastcgi_no_cache $no_cache;
        }

and this is what i have for enabling multi-site

        if (!-e $request_filename) {
                rewrite /wp-admin$ $scheme://$host$uri/ permanent;
                rewrite ^(/[^/]+)?(/wp-.*) $2 last;
                rewrite ^(/[^/]+)?(/.*\.php) $2 last;
        }