Instantiated Game Objects that contain Cameras and use Post Effects have OnRenderImage called twice. This is especially bad in VR, where it gets doubled again and called 4 times.

Reproduction Steps:
1. Build & Run the attached project "case_814402-AA_Repro_UPDATED.zip" for PC or PS4 in 5.3
2. Observe the on-screen text will say OnRenderImage was called once
3. Repeat in 5.4
4. Observe the on-screen text will now say OnRenderImage was called four times

Expected Result:
OnRenderImage should only be called once in 5.4, as it was in 5.3.