Caprica problem

There's some strange thing:
If I compare frame 396 from the first and second submit, the the perspective kinda changed.

In blender you got like 3 boxes when you look through the camera (keypad 0)
The outer solid box - the second and third dotted box within that.

It looks like on the first rendering, there was everything rendered till the solid border, on the second render it's whats inside the dotted box.

Has that been my mistake? I didnt change anything on the camera between 1. and 2. submit as far as I remember.

Or do I get something wrong here?