Iam serving my static content with ngnix.

location /static {
      alias /opt/static/blog/;
      access_log off;
      etags on;
      etag_hash on;
      etag_hash_method md5;
      expires     1d;
      add_header Pragma "public";
      add_header Cache-Control  "public, must-revalidate, proxy-revalidate";
}

The resulting header looks like this:

Cache-Control:public, must-revalidate, proxy-revalidate
Cache-Control:max-age=86400
Connection:close
Content-Encoding:gzip
Content-Type:application/x-javascript; charset=utf-8
Date:Tue, 11 Sep 2012 08:39:05 GMT
Etag:e2266fb151337fc1996218fafcf3bcee
Expires:Wed, 12 Sep 2012 08:39:05 GMT
Last-Modified:Tue, 11 Sep 2012 06:22:41 GMT
Pragma:public
Server:nginx/1.2.2
Transfer-Encoding:chunked
Vary:Accept-Encoding

Why is nginx sending 2 Cache-Control entries, could this be a problem for the clients?