I don't think it is a bug, Try adding the MIME type to your .htaccess file For instance, put or add the following content to your .htaccess file (which should be in the same place of your .js or above folders)
#JavaScript
AddType application/x-javascript .js
This solved my tree "Resource interpreted as other but transfered ... " warnings. Everytime you have that kind of warning it means you don't have enough info in your .htaccess file.
BTW1: Since you are modifying .htaccess file, make sure you restart your server.
BTW2: I also could clear same warnings for GIF files in Safari 4 with this:
#GIF
AddType image/gif .gif
BTW3: For other file types: see w3schools list or htaccess-guide