Can someone explain how to fix this visibility issue In the first pic I have two objects in a scene, same layer, and side by side, they look fine, but when I move my view so one is in front of the other, the one in front becomes invisible where it overlaps the one behind it
It sounds like you have switched on 'In Front' for the blue object. 

That's located on the right column (Properties Editor), on the Object Context tab (orange square icon) in the 'Viewport Display' category. There is a checkbox option for 'In Front'.