I have a strange problem which is only occurring on my PC. When I set up a viewport on a new layout, the model is only fully visible when I move my layout to the far left of my screen.
I've added screenshots below, the first shows the whole of the drawing a the paper is as far left on my display as it can go.

The only thing I changed on the second screenshot is to move the paper further to the right, as you can see, it's as if the left hand part of the model has been erased.

Does anyone have any ideas as to why this is happening and how to stop it?