What details do you want? It does what I described any time the topic is long enough. If you want to experience the problem yourself, you need to be using iOS.
As far as I can tell, the screen rendering is taking the dimensions of the full screen, but when typing on-screen the vertical height available is halved (the lower half - approx - being occupied by the pop-up keyboard). The consequence is that no matter what I do, as soon as I hit a key the screen slides down so that the text entry field is hidden by the keyboard and I'm typing blind. What more can I say???
Needless to say, the old forum worked fine. Somebody has buggered this up. Neither did I notice this on the preview - I'm sure I would have done!
Is nobody else seeing this with iOS then, or is nobody else using iOS?