Seriously, never seen this before, I would have thought a texture problem but the UZO/Binocular view is wierd, looks like a vapour trail in windy conditions!
Another guess would be monitor sync lines, video card problem but if it is only in SH3 then it has to be there!
Sorry I can't help, if you find a fix please let us know, Im intrigued!
Edit: Is it there randomly or all the time?