[Plugin: W3 Total Cache] Problem with "User is logged in" when I'm not logged in

The first time I access the page http://www.porlolitasbysyrah.com/bienvenido-a-nuestra-web/, the debug shows this information:

<!– W3 Total Cache: Page cache debug info:
Engine: disk: enhanced
Cache key: bienvenido-a-nuestra-web/_index.html
Caching: enabled
Status: not cached
Creation Time: 1.726s
Header info:
X-Powered-By: PHP/5.2.6-1+lenny9
X-Pingback: http://www.porlolitasbysyrah.com/xmlrpc.php
Content-Type: text/html; charset=UTF-8
Set-Cookie: wordpress_polylang=es; expires=Sat, 08-Dec-2012 12:06:02 GMT; path=/
Last-Modified: Fri, 09 Dec 2011 12:06:03 GMT
Vary: Cookie
–>

which I suppose is correct because is the first time I access and the cache file is created in the w3tc/pgcache directory.

However, when I access the page again, I obtain the next information from debug:

<!– W3 Total Cache: Page cache debug info:
Engine: disk: enhanced
Cache key: bienvenido-a-nuestra-web/_index.html
Caching: disabled
Reject reason: User is logged in
Status: not cached
Creation Time: 1.607s
Header info:
X-Powered-By: PHP/5.2.6-1+lenny9
X-Pingback: http://www.porlolitasbysyrah.com/xmlrpc.php
Content-Type: text/html; charset=UTF-8
Set-Cookie: wordpress_polylang=es; expires=Sat, 08-Dec-2012 11:50:44 GMT; path=/
–>

Debugger tells me that I’m logged in, but it is not true :¬). The result is that no cache file is served and no more pages are cached in w3tc/pgcache when I navigate through the rest of the site.

Do you know what’s the reason for this erratic behaviour?

Thanks in advance.

http://wordpress.org/extend/plugins/w3-total-cache/