Ed, today i have had three instances where I have made a post and hit submit and the post hasn't appeared. Posting again always seems to work. I don't usually check that my post has appeared so I am not sure if the post has appeared and vanished again or if it has never appeared. They weren't silly or offensive posts so I don't think that they have been removed by a mod or an ed.
Ed, I have found recently that I have to press submit at least twice before the answer is submitted successfully. I also have a lot of blue and white squares when I scroll up or down on a recently opened page.
I had a car like that, it kept going completely dead, I would get the AA out and miraculously it would work again, very embarassing...it took a year to find out that it was a rotting HT lead and the car was brand new!