Reproduction steps:
1. Open the attached project (WaterTest.zip);
2. Open the Main.unity scene;
3. Click on the WaterCamera;
4. Try to change the scene view by right-clicking on the mouse in any random position;
5. In the Camera Preview, observe that the skybox is still reflected from the water, even if Clear Flags of this camera is set to Depth only;
6. Build the project (File->Build&Run);
7. Observe that water is not reflecting the skybox as it should.

Expected result: in the game view and in the built project the water reflection is the same;
Actual result: in the game view water reflects skybox.

Note: the user has attached the screenshot of which shows the difference.

Reproduced on: 5.3.5p8, 5.4.2p3, 5.5.0b11, 5.6.0a3.