I have this issue and i cannot find the reason. Newly created pages come and goes on both the website and in edit-mode. My first thought was something was missing in the templates (like cache control), but than i discovered that the pages ware missing in edit-mode as well, which has nothing to do with the templates. I think it has something to do with output cache, but i'm not sure. This is a single server installation, it would make much more sense if it was a multiserver installation.... any ideas?