I read over these posts, and it appears the vast majority of you Knocked out Minthara before speaking to/freeing Halsin from prison. I finished an Honour Mode playthrough last month, where I recruited Halsin and killed Minthara. I went back and opened up the journal entry, and here is the sequence:
If you look at the objectives from the bottom up, I actually defeated Gut and freed Halsin before I went to kill Dror and Minthara. This is just a suggestion, but have any of you tried freeing/speaking to Halsin BEFORE you knock out Minthara? This way the journal entry has a chance to update? I normally just ask Halsin to go somewhere safe. If you choose to talk to Halsin first, I would go Knock out Minthara second, Kill Dror third. If you attack Dror before knocking out Minthara, I believe this will aggro the entire goblin camp.
When I spoke to Halsin in prison before attacking the goblin camp, he asks me to take care of the remaining leaders, Minthara and Dror. After I killed all the goblin leaders, I couldn't find him in prison or the entire Goblin Camp. I ended up finding him in the Emerald Grove, as he returned on his own.