Root term in Pathauto only works for child terms? My taxonomy structure looks like this:

Film
- Short film
- Special film


Using Pathauto, I would like the url to always include the root term. 

So for nodes tagged with 'film' the path is: film/node-title. For nodes tagged with 'short film' the path is also: film/node-title

I thought the 'root term' token would do the trick, setting pathauto pattern to: [node:field-category:root:name]/[node:title]

But it only works for children. If a film is tagged 'film', the token isn't used for some reason. Perhaps I am misunderstanding the meaning of 'root'?
I encountered the same problem and wrote the patch for token module
Here is patch https://drupal.org/node/2050421#comment-7806099