apparently you can use it if you use it from your pet bar. if you have Command Pet bound on your main bar, it does not work.
seems they made fortitude of the bear a passive instead of a defensive CD and when they did that they probably broke the ability to use the Command Pet abilities
Edit: To clarify, Primal Rage (Ferocity Ability) is working. Primal Rage (Command Pet Ability) is broken. If you have a Ferocity pet out and search Primal Rage in your spellbook, youll see both and can move the Ferocity one to your bar.