title: Rails only precompiles *some* files on production
body: <p>I have a strange issue where only <em>some</em> of our assets are being pre-compiled on production. Our <code>application.css</code> file is compiled and updated, but our <code>mobile.css</code> file hasn't been compiled since July, and the site still points to this older version.</p>
  
  <p>Stranger still, we don't get this problem on our staging or local environments. All assets are precompiled and the latest versions are served on the site.</p>
  
  <p>In July we upgraded the site to rails 4 and changed our configuration to this:</p>
  
  <pre><code># Rails 4 changed the precompile to only for app/assets. This will include vendor/assets
  config.assets.precompile &lt;&lt; Proc.new{|filename, path| %w(.png .gif .css .js .htc .svg .eot .woff .ttf).include?(File.extname(filename)) &amp;&amp; path =~ /(\/lib\/assets)|(\/vendor\/assets)/ }
  
  
  config.assets.precompile += [
    'form.css',
    'homepage.css',
  
    …
  
    #mobile
    'common_mobile.css'
  ]
  </code></pre>
  
  <p>Any ideas on what could cause this?</p>