the first is a warning and can be safely be ignored. but if you want you can setup reddis instead of APCu.
the second sounds like a bug. I suggest you post a bug on github to help get it resolved.
		
		
	 
Thanks man it works great now.
I have another issue now. I cannot share files with other users/groups. When I type I don't get autocomplete or even it I type full name I get nothing.
The sharing settings are turned on and the users belong to the same group with one user as group's admin.
edit: only thing I did different was add https. like cyberjock said.
I also added
	
	
		
		
			add_header Strict-Transport-Security "max-age=15768000; includeSubDomains; preload;";
add_header X-Content-Type-Options nosniff;
add_header X-Frame-Options "SAMEORIGIN";
add_header X-XSS-Protection "1; mode=block";
add_header X-Robots-Tag none;
		
		
	 
to get rid of other warning from 
official documentation
full config:
note: there are more changes I took from official doc but they were done later on and this issue was already there.
Code:
worker_processes  4;
#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;
#pid        logs/nginx.pid;
events {
    worker_connections  1024;
}
http {
    include       mime.types;
    default_type  application/octet-stream;
    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';
    #access_log  logs/access.log  main;
    sendfile        off;
    #tcp_nopush     on;
    #keepalive_timeout  0;
    keepalive_timeout  65;
    gzip  off;
    server {
    listen 443 ssl;
    ssl_certificate /usr/local/etc/nginx/server.crt;
        ssl_certificate_key /usr/local/etc/nginx/server.key;
    add_header Strict-Transport-Security "max-age=15768000; includeSubDomains; preload;";
      add_header X-Content-Type-Options nosniff;
      add_header X-Frame-Options "SAMEORIGIN";
      add_header X-XSS-Protection "1; mode=block";
      add_header X-Robots-Tag none;
        ssl_session_cache    shared:SSL:1m;
        ssl_session_timeout  5m;
        ssl_ciphers  HIGH:!aNULL:!MD5;
        ssl_prefer_server_ciphers  on;
    root /usr/local/www;
        location = /robots.txt { allow all; access_log off; log_not_found off; }
        location = /favicon.ico { access_log off; log_not_found off; }
    rewrite ^/caldav(.*)$ /owncloud/remote.php/caldav$1 redirect;
    rewrite ^/carddav(.*)$ /owncloud/remote.php/carddav$1 redirect;
    rewrite ^/webdav(.*)$ /owncloud/remote.php/webdav$1 redirect;
        location ^~ /owncloud {
            index index.php;
       rewrite ^/.well-known/host-meta /owncloud/public.php?service=host-meta last;
            rewrite ^/.well-known/host-meta.json /owncloud/public.php?service=host-meta-json last;
       rewrite ^/.well-known/carddav /owncloud/remote.php/carddav/ redirect;
           rewrite ^/.well-known/caldav /owncloud/remote.php/caldav/ redirect;
       rewrite ^(/owncloud/core/doc/[^\/]+/)$ $1/index.html;
            try_files $uri $uri/ /owncloud/index.php$is_args$args;
            error_page 403 /owncloud/core/templates/403.php;
            error_page 404 /owncloud/core/templates/404.php;
            client_max_body_size 10G;
            fastcgi_buffers 64 4K;
            location ~ ^/owncloud/(?:\.|build|tests|config|lib|3rdparty|templates|data|autotest|occ|issue|indie|db_|console) {
                deny all;
            }
            location ~ \.php(?:$|/) {
                fastcgi_split_path_info ^(.+\.php)(/.*)$;
                fastcgi_pass unix:/var/run/php-fpm.sock;
                fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
                fastcgi_param PATH_INFO $fastcgi_path_info;
                fastcgi_intercept_errors on;
        fastcgi_param modHeadersAvailable true;
        fastcgi_param HTTPS on;
                include fastcgi_params;
            }
            location ~* \.(?:css|js)$ {
           add_header Cache-Control "public, max-age=7200";
            # Add headers to serve security related headers
            add_header Strict-Transport-Security "max-age=15768000; includeSubDomains; preload;";
            add_header X-Content-Type-Options nosniff;
            add_header X-Frame-Options "SAMEORIGIN";
            add_header X-XSS-Protection "1; mode=block";
            add_header X-Robots-Tag none;
            access_log off;
            }
            location ~* \.(?:jpg|jpeg|bmp|swf|gif|ico|png|css|js|svg)$ {
        access_log off;
                expires max; add_header Cache-Control public;
            }
        }
}