This really is quite a large problem for people who drive in first person. Reversing a truck with mirrors that utterly misrepresent the area behind it is frustrating to say the least.

Experiencing desync issues after this patch as well, although not as severe as described. The delay of gunfire in multiplayer is several seconds however and entities (AI, Players, vehicles) zip around all over the place despite a desync value of 0.

Have the same issue on dev build 1.05.111807

This issue is still present in 1.26.126789.
In addition, shifting left/right is also reversed.

Issue has been resolved.

i7 4770k @ 4.3 GHz
GTX 780 @ 1.2 GHz core, 1.6 GHz memory
16 GB RAM @ 2133 MHz
256 GB SSD

I get 20-30 fps at times (in campaign/showcases), and very, very rarely does it go above 60 fps, regardless of video settings. The only thing that seems to have any noticable effect at all on the framerate is the render/object render distance setting.

The highest CPU thread utilization usually hangs around 60-70%, GPU 30-50%.
While paused and in the video setting menu, the fps is usually about three to four times as high as while unpaused.