Steps to reproduce:
1. Open "CommandBuffers.7z" attached project
2. Open "test" scene and enter Play mode
3. Observe "Layer2" panel being blurred out and overlayed with an outline of the original text

Expected outcome: Before applying Post processing effects the Alpha channel is saved and applied afterwards. As such it should apply this Alpha channel information and the result should have the text blurred out and Cut to the edges of the original text.
Actual outcome: Alpha channel information is partially saved, but applied as an overlay image after the Post Processing has been done.

Reproduced on 2017.1.0b4, 2017.1.0b6

Notes: Any version lower than 2017.1.0a6 throws "CS1644: Feature `null propagating operator' cannot be used because it is not part of the C# 4.0 language specification" error

By Design:
The post-processing stack needs the alpha channel to store information for a few effects for performance reasons (depth of field stores CoC info in alpha, anti-aliasing hijacks the alpha channel as well for various things, etc). As camera post-processing is generally applied as a last step it's usually not an issue (in the most common case anyway). That's not something we can fix without tanking performances and dropping support for a few lower end platforms unfortunately.