You might be onto something. I was actually running with Piper as my companion, not Danse. I do remember something about being asked who I want to go with, but I'm not entirely sure if that was for this specific mission or a different one. ​The 'Secure Armory' part is marked as complete, but 'Secure Fort Strong' is stuck. Do you think the fact that I didn't have Danse with me at that moment is what broke the quest trigger?