Thanks Eric. I added my signature with version info.
In the meantime, I solved the subject problem. The problematic wall was checked as "no room definition". Not sure why, but I had some nearby rooms with ceiling issues. I had tried to unclick box this a few times and my roof went crazy. So, I turned off "auto build roof", then unchecked
"no room definition", and it worked.
I have a few other issues that I will post if I can't figure them out.
MikeInMich's post in Joining two walls was marked as the answer