To reproduce:
1. Open attached Unity project "CanvasTest2.zip"
2. Open scene "scene1"
3. Go into Play Mode

Expected result: Image should not be rendered by the camera since its Layer is not selected for rendering
Actual result: Image is rendered despite being on a custom Layer which is not selected to be rendered by the camera

Reproduced on: 5.4.5p1, 5.5.3p3, 5.6.1f1, 5.6.1p1, 2017.1.0b6

Note: added a gameObject called "SameLayerNotRendered". It has the same layer as the "Image" gameObject and it does not get rendered.

Note: Attached image "CustomLayerRendered.png" in which DoNotDisplayMe Layer is selected for rendering and renders both objects in that Layer (Image and SameLayerNotRendered) and another image "CustomLayerNotRendered.png" in which only UI Layer is selected for rendering, but Image is still rendered despite being on on a custom Layer not selected for rendering.