Rudi, I've noticed this , too. It seems only to happen in Omni, particularly Omni when accessed via the Travel forums. I've seen it enough times to confidently say that there seem to be no posts missing; the reference to the additional "non-existent" page seems to be a harmless "bug".
P.S. It's almost 2 March here in Europe, so I'm wishing you a very happy birthday. Enjoy your day.