Okay. I got it working.
I spent all day trying to figure out what was wrong. What I had to do, was to change all the permalinks of the posts made with Avia Layout Builder. This was just for the existing posts.
I made a new entry with the Avia Layout Builder, and it worked fine. Now comments will show both in my website, and in my websites Facebook page. :)
I tried removing all the coding from a post made with advanced layout builder, and voila, Facebook Comments worked fine with notifications on that post. I think there is something blocking FB from seeing the comments when I’m using advanced layout builder.
Best regards
Kjetil