Ack, figured it out. Firefox was caching the permanent redirect. Once I told firefox to forget about the site it started working!

To clear a permanent redirect cache in Firefox, you can open your browser history, search for the site you want to remove the redirect for, select it, and then right-click to choose "Forget this site" - this will effectively clear the cached redirect information for that website; ensure all tabs related to the site are closed before doing this.