Reproduction steps:
1. Open the attached '960206_UIScreenSpaceCamera' Unity project.
2. Open and play the 'Main' scene.
- Notice, that panel is centered (Actual/Expected behavior screenshots attached).

Note:
- Panel stays in the corner of the screen when Render mode is set to Screen Space - Overlay (Expected for Screen Space - Camera ).

Reproduced with:
Editor, Standalone
5.6.4p1, 2017.1.2p1, 2017.2.0f3, ,2017.3.0b5

RESOLUTION: By design. The problem with the project was user error. The structure of the UI was as follows:

- Canvas
- Panel
- Camera
- Rest of panel contents

Any change to the RectTransform of the Panel also applies to the camera within it, so naturally the panel is always centered regardless of transform settings. The correct structure is the following:

- Canvas
- Camera
- Panel
- Rest of panel contents