Postprocessing: Gets graphics glitch when script does camera target texture changes. (New in 5.6)

1. Download attached project (PostProcessingProejct.zip)
2. There is a gameobject with an attached script that renders the main camera to a temp rendertexture, and then resets the camera target texture when you click the onscreen button
3. In editor, run the project, observe postfx is displayed properly
4. click on the button, observe the postfx seems to render incorrectly

Note: This is not just an editor bug, it reproduces on standalone as well as on android device
See video of problem compared to 5.5 as well: (PostProcessing.avi)

Reproducible in : 5.6.0b5
Not-reproducible in : 5.5.0f3