During "Commander without a Cause", after filling out the "Investigate the camp for information" objective, the quest softlocks. Arina comes up to the horn and is supposed to sound it, but nothing happens instead and she just stands there. The same happens if the timer runs out before all the information is investigated. Me and my friends tried to do the quest multiple times and it always ends in a softlock.
Edit: I found a temporary workaround.
If you're facing this issue, here's what you need to do to push the quest forward.
Enter the instance
Proceed through the quest until you have approached the camp and eavesdropped the conversation
Wait 7 minutes for the hunting party to leave (the timer gets visible only when 2 minutes are left)
(Important) Do not pick up the disguise at any point
Wait for Arina to come close to the horn and make sure she stands still
Walk into her detection cone. She will draw her weapon at you, making her reset her script
After you're booted out of the camp, the quest will progress