Corruption in Killing Floor 2 with recent versions

I get minor issues, like loading screen not showing properly (strange letter box effect), and shadows are flickering.

But one major issue is that the geometry can just completely disappears in parts of maps, it's somewhat controlled by the flashlight, but not deterministic enough to pin down, the glitchy corruption still applies when the all effects are disabled.

This was not present in an old version (maybe ~ 3.1).

Here's an example: www.twitch.tv/videos/273822001?t=00h25m17s

Another: www.twitch.tv/videos/273822001?t=00h27m11s

Strange letterbox effect: www.twitch.tv/videos/273822001?t=00h13m39s

I reverted back to 3.0, and the glitching is still there, must have been something else, maybe driver update, or game patch that broke it.