Issue: Fetal error in creating headers

When I want to create a header for a subforum I get the following error:

After getting this error, the header article will exist in headers subforum(namespace) and in normal forums header as well but when I try to open or edit it, it is like the header article page doesn't exist and I will be directed to creating a new one. However when I try to save that new page, I will get a message explaining that this page already exists!

The issue can be solved by moving that orphaned header article to Island and move it back to headers forum(namespace).

regards,

P.S: I have recently upgraded vb from 3.8 to 4.1.1. I don't remember this issue existed on 3.8 or not cause before, I hadn't used headers much.