Z-fighting alike artifacts in 4.12 ? GBuffer errors?

After switching to 4.12 I’ve got z-fighting alike artifacts on many objects.
They were ok in 4.11 so I assume it’s somehow related to the the GBuffer format changes
Can I somehow fix it, or switch to legacy GBuffer?
Strangely, bugs disappear if I make material 2-sided.

https://dl.dropboxusercontent.com/u/5836728/z-fighting.PNG

UPD: It turned out that G-Buffer depth doesn’t affect much this bug.

Though it was removed by setting Early Z-pass to NONE.