I haven't had a problem though I did do things in a different order.
I did the Marcus fight and saved the inn.
Spoke to the people in the inn about Art.
Spoke to Halsin in camp who then shot off to the inn.
Spoke to Halsin in the inn and got the clue about finding the 'something with a connection'
Went out in the Shadow-Cursed area and found the thing.
Cmae back to the inn and did the needful.
Halsin shot off to 'the lake' where we are to meet him.
I completely forgot about this due to getting involved in another side-quest. That was the night before last. I've not been in the game since then and only remembered about Halsin earlier today.
Now I'm wondering if he will be alive.

If you got that far, he might be safe.