Reproduction steps:
1. Open the attached project in Unity
2. Open the Bug Example scene
3. Select the Default Camera gameObject.
4. In Camera Preview observe that it shows all of the Canvas objects, while some of them have different layers than the Default Camera gameObject
5. Select the Camera1 or Camera2 gameObject and observe that they don't display Canvas objects with respective layers.

Expected result: Default Camera, Camera1 and Camera2 only render those objects, which are on their layers.
Actual result: Default Camera renders all images, even if some of them are on different layers.

Workaround:
1. In the Hierarchy, create three Canvas gameObjects;
2. Attach UI images to each of them;
3. Change their layers to Default, Camera1 and Camera2;
4. In the Inspector, set Render camera to particular camera, which has to render the image.
5. OR open the attached project https://fogbugz.unity3d.com/default.asp?ixAttachment=152528&pg=pgDownload&pgType=pgFile&sFilename=UIRender.zip

The bug could be reproduced on 5.2.4f1, 5.3.6p5, 5.4.1f1 and 5.5.0b4 Unity versions.