No, Thiggy, It is not a quirk in the forum. I have done it myself a few times. It appears that after you post something and then use the back buttom, without paying attention and then hit the wrong key, you will double post. My method is a around about, after posting I just go to the top of the forum amd redect on ‘fix-it-forum’, that way I don’t double post.
Let us know how it works out.