title: Wordpress incorrectly serving page with content type plain/text
body: <p>I have a wordpress site that I host my blog on. Recently, without any (conscious) change to the configuration I started hitting issues where the main index page was being served with a <code>Content-Type</code> of <code>text/plain</code> rather than the correct <code>text/html</code> - leading to visitors seeing the source code, rather than the rendered page.</p>
  
  <p>I'm using the W3TC Browser Cache plugin and narrowed down the problem to this portion of <code>.htaccess</code> file:</p>
  
  <pre><code>&lt;IfModule mod_rewrite.c&gt;
    RewriteEngine On
    RewriteBase /
    RewriteCond %{HTTP:Accept-Encoding} gzip
    RewriteRule .* - [E=W3TC_ENC:_gzip]
    RewriteCond %{HTTP_COOKIE} w3tc_preview [NC]
    RewriteRule .* - [E=W3TC_PREVIEW:_preview]
    RewriteCond %{REQUEST_METHOD} !=POST
    RewriteCond %{QUERY_STRING} =""
    RewriteCond %{REQUEST_URI} \/$
    RewriteCond %{HTTP_COOKIE} !(comment_author|wp\-postpass|w3tc_logged_out|wordpress_logged_in|wptouch_switch_toggle) [NC]
    RewriteCond %{HTTP_USER_AGENT} !(W3\ Total\ Cache/0\.9\.4) [NC]
    RewriteCond "%{DOCUMENT_ROOT}/wp-content/cache/page_enhanced/%{HTTP_HOST}/%{REQUEST_URI}/_index%{ENV:W3TC_PREVIEW}.html%{ENV:W3TC_ENC}" -f
    RewriteRule .* "/wp-content/cache/page_enhanced/%{HTTP_HOST}/%{REQUEST_URI}/_index%{ENV:W3TC_PREVIEW}.html%{ENV:W3TC_ENC}" [L]
  &lt;/IfModule&gt;
  # END W3TC Page Cache core
  </code></pre>
  
  <p>If I remove this section from the <code>.htaccess</code> file, that page loads fine, with the correct <code>Content-Type</code>. However W3TC likes to reinstate this block some time after I remove it, and the problem returns. </p>