Yes, things changed from 12 to 13. Leonid helped me unravel this mystery.

In the event that your breadcrumbs (the handy menu at the top of certain pages) suddenly ceased to appear, you can remedy this by deleting or changing the name of the breadcrumb.html file in the module / template folder.

(It's best just to remove the file. Because it can change the hash and keep the module from updating later.)