I went to Ashran, as per the "Outpost Building Assembly Notes" item's description, and found the vendor "Kinkade Jacobs". I went through her available garrison blueprints, only to find the "Garrison Blueprint: Dwarven Bunker. Level 2" was not available.
Is this found elsewhere, or is this just one of those bugs?
EDIT: Another player next to me said he could see it, but I could not. Definitely a bug then.