I’ve come across a replicable bug to do with the parallel projection camera setting. Sometimes when using parallel projection some portion of the bottom of the screen will be “clipped” i.e. won’t show.
I just realised that this happens when you are initially in perspective camera mode and zoomed in very close, and then change to parallel projection.
It seems that the parallel mode is using the ‘closeness’ information from where the perspective mode was left. So even when you zoom very far out in parallel mode it still clips the section that would be clipped in perspective.