There is a problem with trailing slashes. I will try to explain in a few steps (I have wp-supercache 0.6.7 installed):
1. we all know that http://www.example.com/page is not the same with http://www.example.com/page/ (google knows that too and may consider this duplicate content)
2. the default behavior of wordpress for missing trailing slash is to 302 redirect (temporarily redirect) the http://www.example.com/page to http://www.example.com/page/
3. after installing wp-supercache, it seems that http://www.example.com/page is the same with http://www.example.com/page/ because if I request (from cache), let's say http://www.example.com/page (without trailing slash) it returns (from cache) the same copy of the page http://www.example.com/page/ (with trailing slash) instead of 302 redirecting it to http://www.example.com/page/
4. what happens next ? google will index both pages with 100% duplicate content witch is very wrong.
Can this be fixed ?