I think what caused it was bad quote formatting on his last post in the current round thread.
It may have been the cut and paste
It did have something to do with posting a URL. You have to make 3 posts without posting a URL before you include one in a post and I believe this includes your signature as well.
If you think about it, it does make sense.
Actually Tech had mentioned this before and I vaguely remembered but obviously forgot about the 3 URL free post requirement.
Also the funny post that KP had mentioned is that as a spammer the post is entered but only Moderators and above see it. It's highlighted in a funky way to indicate that it needs to be approved before it becomes visible to everyone. I believe that if KP had realized this he should have been able to approve the post and that by itself *might* (I'm not sure of this) have been enough to change Ragnar back to a Member.
Like I said I'm not sure about this but it would be worth checking out if and when this ever happens to anyone else. That is of course if you happen to remember this conversation in however many months from now that the issue comes up again.