Shader properties can be used for changing blending mode of a shader pass with using square bracket notation (e.g. "Blend [_Foo] [_Bar]").
However, it seems Graphics.Blit ignores these shader properties on 5.5.0.

Note: Graphics.Blit works properly if SetPass() is used.

Reproduction Steps:
1. Import attached project "GraphicsBlitRegression".
2. Open "Test" scene.
3. Enter Play mode.

Expected result: Unity draws a transparent gradient properly.
Actual result: Unity draws opaque black screen.

Reproduced on: 5.6.0b3, 5.5.0p3
Not reproduced on: 5.4.3p3, 5.3.7p2, 5.2.5f1