I'm running in multisite mode. The home and all pages work perfect with or without WP Super Cache. When I activate and configure the plugin something happens on the sub sites. The top html tag and a few other tags down the page get funny (or at this point not so funny) like this.
Cached page Injects <img src="
where there should only be ="
<html xmlns<img src="http://www.w3.org/1999/xhtml"> <head>
Goes away when I turn off WP Super Cache is back off. My setup is using Nginx fronted apache.