When pressing F5, the world behind player only loads from when you move your mouse

When you change perspective from 'front view' to 'back view' the world you would have to see, doesn't load untill you move your mouse.

In the screenshots you see, when i switch from 1st person view to my front view, the world doesn't load behind me, untill i move my mouse.

Then, when the world is loaded, i switch back to 1st person view, and again, the world i need to see doesn't load untill i move my mouse.