Проблема с nginx proxy_pass - получение 404

Я немного сбит с толку и совсем не понимаю, почему я получаю 404 Not found по запросу http:/customer.local/sign-out Странно то, что это происходит только в браузере Firefox с CURL или Chrome, он отлично работает. Вот моя конфигурация nginx. Конечная точка /sign-out ответов с 302, что ожидается. Но ответ Firefox - 404.

upstream cd_tomcat {
        server 127.0.0.1:9180;
}

upstream ua_tomcat {
        server 127.0.0.1:9080;
}

    server {
            listen 80;
            listen [::]:80;
            server_name customer.local;

            proxy_hide_header X-Frame-Options;
            proxy_hide_header X-XSS-Protection;
            proxy_hide_header Strict-Transport-Security;
            proxy_hide_header X-Content-Type-Options;
            proxy_hide_header X-Nexmo-Disable2FA;
            proxy_hide_header X-Nexmo-Trace-Id;


            add_header X-Frame-Options sameorigin always;
            add_header X-XSS-Protection "1; mode=block;" always;
            add_header Strict-Transport-Security "max-age=31536000; includeSubdomains" always;
            add_header X-Content-Type-Options nosniff always;

            proxy_connect_timeout 1s;
            proxy_read_timeout    120s;

            # reverse proxy headers

            proxy_set_header Host $host;
            proxy_set_header Connection "";
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Strict-Transport-Security max-age=15768000;


        location = /sign-out {
            proxy_pass http://ua_tomcat;
        }

        location / {
            limit_except HEAD GET POST DELETE PUT {
                deny all;
            }
            proxy_pass http://cd_tomcat;
        }

    }

Ответ Chrome:

Request URL:http://customer.local/sign-out
Request Method:POST
Status Code:302 Found
Remote Address:127.0.0.1:80
Referrer Policy:no-referrer-when-downgrade

Response Headers
view source
Cache-Control:no-cache, no-store, max-age=0, must-revalidate
Connection:keep-alive
Content-Language:en-US
Content-Length:0
Date:Thu, 11 May 2017 00:29:07 GMT
Expires:0
Location:http://customer.local/sign-in
Pragma:no-cache
Server:nginx/1.10.0 (Ubuntu)

Request Headers
Accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Encoding:gzip, deflate
Accept-Language:en-US,en;q=0.8
Cache-Control:max-age=0
Connection:keep-alive
Content-Length:42
Content-Type:application/x-www-form-urlencoded
Cookie:ajs_anonymous_id=%224271d2c1-8a46-496f-ace1-c8834409057e%22; km_ai=hx%2BHamG8gzdMvH4JRxc09nlXMnY%3D; _gat=1; _dc_gtm_UA-20475086-1=1; km_lv=x; SESSION=116bd916-a441-42a3-8cc0-5bf397324c33.dev1.peter; ajs_group_id=null; ajs_user_id=null; DWRSESSIONID=qHJkIWiZijOADHxDUbYZeP0NVBxinfhDQLl; kvcd=1494462543395; km_vs=1; __ar_v4=5J6GBCUY75GLBH2KZNAP4J%3A20170509%3A12%7C4INKOFBHJNDVXOG5I2YP4W%3A20170509%3A12%7CPJYNR5FAJJBTHGC5IKPIUR%3A20170509%3A12; _ga=GA1.2.900688302.1494457586; _gid=GA1.2.1957585239.1494462547; _gat_UA-20475086-1=1
Host:customer.local
Origin:http://customer.local
Referer:http://customer.local/
Upgrade-Insecure-Requests:1
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36

error.log пуст. В журнале доступа есть

127.0.0.1 - - [11/May/2017:00:26:31 +0100] "GET /sign-out HTTP/1.1" 404 0 "-" "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0"
127.0.0.1 - - [11/May/2017:00:26:33 +0100] "GET /sign-out HTTP/1.1" 404 0 "-" "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0"