I think the Forum is trying to tell you something.

I find the posts very entertaining. Wow.

Dale
This is an older style forum which none of us has a way of altering its setup nor are there really any explanation pages. We just go with what is and don't get too carried away with they "why's" of the forum. It just is.
I too have had the same issue from time to time. It seems to happen if I am the last post on the thread and want to comment further in another post. So, while it is still under that same thread, I just change a word in the subject line. I keep the RE:

"It seems to happen if I am the last post on the thread and want to comment further in another post. "

Thank you Zoo for that hint, it's reassuring that I'm not the only victim of this glitch