Nginx expires seem wrong

I've just reinstalled my machine to remove old dependencies and install things in a more proper way and I've just realised the cache seems wrong now.

Headers are as follow for an image:

cache-control:max-age=300
content-type:image/png
date:Wed, 09 Nov 2016 13:17:50 GMT
expires:Wed, 09 Nov 2016 13:22:50 GMT
last-modified:Wed, 09 Nov 2016 12:25:44 GMT
server:nginx/1.11.5
status:200

As you may see the expire is 5m. However the cache block is set to this:

  location /assets {
    alias /var/www/f13/content/themes/lechuck/assets;
    access_log off;
    expires max;
  }

So it should be 10y.

Here's the whole file:

# sets the proxy cache path location, max size 2g
proxy_cache_path  /usr/local/nginx/cache  levels=1:2 keys_zone=STATIC:100m inactive=24h max_size=2g;

# uses the defined STATIC cache zone
proxy_cache             STATIC;

# cache 200 10 minutes, 404 1 minute, others status codes not cached
proxy_cache_valid 200 10m;
proxy_cache_valid 404 1m;

proxy_cache_key "$scheme$host$request_uri";
proxy_cache_use_stale   error timeout invalid_header updating http_500 http_502 http_503 http_504;
proxy_http_version 1.1;

# transfers real client IP to your ghost app,
# otherwise you would see your server ip
proxy_set_header        X-Real-IP        $remote_addr;
proxy_set_header        X-Forwarded-For  $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header Host $http_host;

client_max_body_size  20m;
client_body_buffer_size    128k;

# default expires (browser cache) set to 1 minute
expires 1m;

# gzip every proxied responses
gzip_proxied any;

# gzip only if user asks it
gzip_vary on;

# gzip only theses mime types
gzip_types text/plain text/css application/x-javascript text/xml application/xml application/xml+rss text/javascript application/json application/javascript;
gzip_static on;

# add a cache HIT/MISS header
add_header X-Cache $upstream_cache_status;

# do not show incoming Etags, if-modified-since is sufficient
proxy_hide_header Etag;

# server {
#       listen         80;
#       server_name    funcion13.com;
#       return         301 https://$server_name$request_uri;
# }

server {
  listen 80;
  listen 443 ssl;
  server_name funcion13.com;

  root /var/www/f13/;

  include /usr/local/nginx/conf/nginx-ssl.conf;
  ssl_certificate_key /etc/letsencrypt/live/www.funcion13.com/privkey.pem;
  ssl_certificate /etc/letsencrypt/live/www.funcion13.com/fullchain.pem;

  return 301 https://www.funcion13.com$request_uri;
}

server {
  listen 80;
  listen 443 ssl http2 default_server;
  listen [::]:443 http2 default_server ipv6only=on;

  server_name www.funcion13.com; # Replace with your domain

  include /usr/local/nginx/conf/nginx-ssl.conf;
  ssl_certificate_key /etc/letsencrypt/live/www.funcion13.com/privkey.pem;
  ssl_certificate /etc/letsencrypt/live/www.funcion13.com/fullchain.pem;

  root /var/www/f13/;
  index index.html index.htm;

  client_max_body_size 10G;

  pagespeed on;
  pagespeed FetchHttps enable;
  pagespeed RewriteLevel CoreFilters;
  pagespeed EnableFilters move_css_above_scripts;
  pagespeed EnableFilters defer_javascript;
  pagespeed EnableFilters lazyload_images;
  pagespeed EnableFilters inline_google_font_css;
  pagespeed EnableFilters prioritize_critical_css;
  pagespeed UseExperimentalJsMinifier on;
  pagespeed EnableFilters insert_dns_prefetch;
  pagespeed EnableFilters collapse_whitespace;
  pagespeed LoadFromFile "https://www.funcion13.com/content" "/var/www/f13/content/";
  pagespeed LoadFromFile "https://www.funcion13.com/assets" "/var/www/f13/content/themes/lechuck/assets/";
  pagespeed SslCertDirectory "/etc/ssl/certs";

  # Needs to exist and be writable by nginx.  Use tmpfs for best performance.
  pagespeed FileCachePath /usr/local/nginx/ngx_pagespeed_cache;

  # Ensure requests for pagespeed optimized resources go to the pagespeed handler
  # and no extraneous headers get set.
  location ~ "\.pagespeed\.([a-z]\.)?[a-z]{2}\.[^.]{10}\.[^.]+" {
    add_header "" "";
  }
  location ~ "^/pagespeed_static/" {
    expires off;
  }
  location ~ "^/ngx_pagespeed_beacon$" { }

  location ~ /\.well-known\/acme-challenge {
    allow all;
  }

  location / {
    proxy_cache STATIC;
    proxy_cache_valid 200 30m;
    proxy_cache_valid 404 1m;
    proxy_pass http://127.0.0.1:2368;
    proxy_ignore_headers X-Accel-Expires Expires Cache-Control;
    proxy_ignore_headers Set-Cookie;
    proxy_hide_header Set-Cookie;
    proxy_hide_header X-powered-by;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header Host $http_host;
    proxy_intercept_errors on;
    rewrite "\d{4}\/\d{2}\/\d{2}\/([^.]+)(.*)$" /$1$2 permanent;
    rewrite ^(/wp-content/)(.*)$ /old/$2 permanent;
    expires 10m;
  }

  location /content/images {
    alias /var/www/f13/content/images;
    access_log off;
    expires max;
  }
  location /old {
    alias /var/www/f13/content/old;
    access_log off;
    expires max;
  }
  location /dmx {
    alias /var/www/f13/content/dmo;
    access_log off;
    expires max;
  }
  location /assets {
    alias /var/www/f13/content/themes/lechuck/assets;
    access_log off;
    expires max;
  }
  location /public {
    alias /var/www/f13/core/built/public;
    access_log off;
    expires max;
  }
  location /ghost/scripts {
    alias /var/www/f13/core/built/scripts;
    access_log off;
    expires max;
  }
  location ~ ^/(?:ghost|signout) {
    expires 0;
    add_header Cache-Control "no-cache, private, no-store, must-revalidate, max-stale=0, post-check=0, pre-check=0";
    proxy_pass http://127.0.0.1:2368;
  }
}

upstream ghost {
  server localhost:2368;
  keepalive 64;
}

Any idea on what could be going on?