Hi all, back again here! I've nearly finished my first run with Minthara. Starting to find missing reactions from her here and there and I'm not sure if that's intended.
This is not a bug. You just didn't do it the way you're supposed to. I know, I had to learn this the hard way too... Just to be safe, make sure to knock her out before attacking the goblins and she has to be temporarily hostile. If you attack Ragzlin, it will aggro the entire camp including Minthara and you won't be able to recruit her.
Thanks for your answer. I will try this.
I load an old save and did this:
1. Stealed in Front of Minthara. So she became temporary Enemy. Knock her out and she was temporary knocked out.
2. Freed Halsin and defeated the rest of the Goblins
3. Did a long rest.
4. Looked for Minthara in the temple. She was no more ko. to be sure I didn't talk to her.
From my point of view the method sounds more like an exploit than as a feature.