As a KS backer I got the keys for the expansions. I was able to activate and use them, and they still show as valid in my Hidden Achievement account. However, when I went in this morning they all appear as locked. Not sure if this is an HA or Steam issue, and have contacted them as well.
That'll definitely be on our end. Check in the Network tab of the Options menu in the game to make sure you're still logged in to your Hidden Achievement account. We're working on fixing a bug that's currently causing the game to check in every time you run so those will be available for offline play.