varnish caches too many object variances

[Taylan Develioglu]

Hi,

I have some varnish 2.1.3 behavior I cannot explain.

Our backend servers are not adding any 'Vary:' header to responses, but
objects > object_heads by a great difference. 

The ratio objects:object_heads is ~ 2:1.

The vcl is clean and simple:

 sub vcl_recv {
     unset req.http.cookie;

     if (req.request == "HEAD") {
         return(pass);
     }
 }

Is there anything besides 'Vary' that makes varnish cache multiple
objects ? What else could be causing this ?