[Plugin: W3 Total Cache] Only first page visited is cached, then needs to be refreshed

I just installed this on a blog and was testing, I set:

Page Cache – disk enhanced
Minify
Object Cache
DB Cache works, but kills my homepage, so I disabled it

Now, I deleted my cookies, logged out and run a test. Got this on my homepage:

<!-- W3 Total Cache: Page cache debug info:
Engine:             disk (enhanced)
Key:                _index.html
Caching:            enabled
Status:             cached
Creation Time:      0.013s
Header info:
X-Powered-By:       PHP/5.2.14
Last-Modified:      Thu, 09 Dec 2010 19:24:40 GMT
Vary:               Accept-Encoding, Cookie
Content-Encoding:   gzip
-->

Now, when I visit another page, the debug info says:

<!-- W3 Total Cache: Page cache debug info:
Engine:             disk
Key:                w3tc_415705253a867f84a3ed8d3ebd424bbf_page_6af5488d38c93cca7265f96b14399fb5
Caching:            enabled
Status:             not cached
Creation Time:      2.705s
Header info:
Expires:            Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control:      no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma:             no-cache
X-Powered-By:       W3 Total Cache/0.9.1.3
Link:               <https://www.site.com/?p=2831>; rel=shortlink
Last-Modified:      Thu, 09 Dec 2010 19:12:48 GMT
Vary:               Accept-Encoding, Cookie
Content-Encoding:   gzip
X-Pingback:         https://www.terapiaintegral.com/content/xmlrpc.php
Content-Type:       text/html; charset=UTF-8
-->

Unless I click F5 to refresh, it is not cached.

Am I doing something wrong? Or this is the normal behavior of the plugin?

Thanks for your comments