Steps:
1. Open repro scene SRP02
2. Observe game view

There are 3 sets of objects from left to right, each contains :

OPAQUE capsule
-Zwrite On
-Blend SrcAlpha OneMinusSrcAlpha
-Render Queue 2000

TRANSPARENT sphere
-Zwrite Off
-Blend SrcAlpha OneMinusSrcAlpha
-Render Queue 3000

Left : Rendered without replacing their render states
Mid : Rendered with overriding render states using RenderStateBlock
Right : Rendered with overriding render states using RenderStateMapping

Problems:
1. Mid and Right Capsule - Both RenderStateBlock and RenderStateMapping are overriding the render states to Zwrite Off even the script is written to be setting them to Zwrite On (writeEnabled = true). The opaque capsules have Zwrite On originally so mid and right capsule should render skybox the same way the left one does.
2. Right Sphere - it should renders the same with the mid sphere as blend state is overriden to be additive, and it's overriden using the same way the right capsule does.

Reproducible : 2018.1.0b4, 2017.3.0p3