That shot definitely looks like NVidia's new HBAO+ ambient Occlusion rearing its ugly head (it does this in ME).
Interesting, thanks; lemme test.
Okay, the diagnosis is correct - with both Ambient Occlusion Usage set to "Disabled" and Ambient Occlusion Setting set to "Off" in Nvidia Inspector, the issue vanishes. Simply setting usage to "Disabled" but leaving the setting on "High Quality" didn't solve the issue for some reason, fooling me into thinking it wasn't an AO issue. The compatibility bit remains 0x00000020 (Mass Effect) in all cases.
A quick test with AO set on "Quality" rather than "High Quality" shows little improvement, unfortunately :

I'll try lower qualities once I've finished my current work.
About the shaders, I experimented for a bit with the ME2 .usf files BranchingPCFCommon.usf, BranchingPCFModProjectionPixelShader.usf and BranchingPCFProjectionPixelShader.usf -- but I've reverted to the ME1 versions while doing tests about my TiledShot issue.
The old vignette effect that plagued TileShot on (some ? most ? all ?) NVidia cards is still present for me, BTW - using a GeForce 770 with the latest non-beta drivers. The traditional fix of disabling the post-processing on two lines in the bioengine.ini file does work fine, though.