Had the exact same problem.
As i found out this is caused by HDR + AA Filter "Edge-detect"!
My settings :
Textures : High
Scenes : High
CIV Traffic : OFF
Water : High
Visib Range: High
Heat Blur : ON
Shadows : Low
Resolution : 1680*1050
Aspect : 16:10
Monitors : 1 screen
Res Of Cokpit displays : 512
Full Screen: Off
HDR: On
TSSAA: On
MSAA: 4x (will try different settings when i find time to)
AA filter:
"Box" = OK
"Narrow-tent" = OK
"Wide-tent" = OK
"Edge-detect" = BUG
System:
Asus P5Q-E
Intel Q9450
8gig Corsair DDR2 800
Ati HD 4870 1gig
Win-7 64bit