I got a message from Larian support yesterday saying "The team is aware of Halsin not following the party after combat and it will be fixed in an upcoming hotfix or patch." I guess we just have to hope that it's going to be an imminent hotfix or patch!

Does Halsin have any barks for you? Wondering if I should report or if it is a known bug?
Now you say that, I don't think he does. Definitely worth reporting.
I'm also still playing around with the not-following bug. I think he only starts following again now if I *both* save/reload and use wildshape.