We are running into a strange problem where intermittently all of the image src attributes are corrupted. Instead of referencing the real url of the image it references the image at it's full file system path. So instead of "http://mysite.com/wp-content/uploads/2011/01/someimage.jpg" I get something like "http://mysite.com/var/www/html/wp-content/uploads/2011/01/someimage.jpg" or often it will nest repeatedly and I will get something like "http://mysite.com/var/www/html/wp-content/uploads/var/www/html/wp-content/uploads/2011/01/someimage.jpg". This will happen for several minutes and will magically go back to normal. Obviously this results in all of my images being broken while this is occuring. This glitch happens at seemingly random times, sometimes it happens frequently, several times a day, other times it won't happen for days or even weeks.
We are using W3 Total Cache with a cdn so that plugin does a search and replace on those image sources so they point to something like "http://cdn.mysite.com/wp-content/uploads/2011/01/someimage.jpg". At first I thought it was causing the issue but after adding some trace statements it seems to happen before W3 even gets a chance to process the output buffer. I may be mistaken but it seems like its happening from within wordpress itself.
Has anyone experienced this or does anyone have any suggestions of how to troubleshoot this.