Why does Unity render everything twice ?

I used GPU Perf Studio to analyze Unity's draw calls under DirectX11.

Remarks : - everything gets drawn twice into a render target the size of the resolution as if transparency is enabled on everything. Once with FrontCounterClockwise = true, and then false. The first time the pixel shader doesn't sample any texture, the second time, it does. What is this ? It's definetely not occlusion culling as I turned that off and I get the same results. All objects are drawn reverse order both times btw. - terrains are rendered 2 times, twice, and this is even weirder, I see the same draw call with the same vertex/pixel shader being called twice, once with DepthMask on, DepthTest On, the other with DepthMask off,DepthTest On and Blend on as if it had 2 passes. Why would it blend together the same mesh if I just have 1 pass in my custom terrain shader ? And I only got 2( or 5 ) brush textures while my GPU can support up to 32+ sampled textures ?

EDIT : I added 2 screenshots of the same object with the 2 different draw states & shaders. You can also see how it tries to resolve 3 multisampled textures. Special effects don't use multisampling, so 1 is the color buffer, 1 is depth, what's the third one ? It definitely looks like deferred rendering of some sorts even though I checked "Forward" everywhere, even in Player Settings.