For me it´s very noticeable and it´s an utter immersion killer, three very bright blue lines all along the horizon going through clouds and anything.
Happens only when running the game in DX10 mode, DX9 doesnt have the blue lines.
-Happens only at lowish altitudes
-Happens only with Radeon cards.
-Happens only running DX10
Should def be fixed asap as far as Im concerned, biggest and most noticeable bug for me right now, close second being the total failure that is AA right now (Anti Aliasing, not Anti Air).
If those two things get fixed Im a happy gamer