It seems the /forks pages for notebooks always state “This notebook has no published forks.” This is new functionality, maybe I just dropped in at the wrong moment? 
Hi Kelley,
It is indeed new functionality, and this morning we were displaying the fork count including all forks of your notebook: the published ones, as well as the unpublished ones that you’re not allowed to see.
I’ve just pushed an update that counts only published forks — so although the counts will appear lower, you’ll be able to see all of them.
Cheers!