The haunting continues.....after a long time of burning without incident, following the 'fixes' I implemented, the campfire once again went out. In less than a minute it reignited itself. I waited several more minutes and it didn't go out again. So something in the environment was still messing with the smoke flow. If you've watched Firespark81's video on Valheim fire characteristics then you know it behaves like a single blob and not like a bunch of particles.
In the screenshot above that shows the top down view of the campfire it hangs over the edge of the wall. Directly below it is a hearth. The room the hearth is in has a big smoke outlet on one side at the roof line but it also has access to the campfire location.
Could the hearth's smoke 'blob' be randomly interfering with the campfire's blob? In effect trying to stuff 2 blobs into a space that can hold only one?
I then built a barrier wall underneath the campfire that totally separates the hearth room from the tower campfire.
So far so good - lol, we'll see.

(being somewhat of a pyro I'm quite interested in these mechanics