tested on two different computers with different cpu/gpu and different settings (both win7 64-bit though)
screenshots:
http://cloud-3.steampowered.com/ugc/506952824860411022/A15367193A7E526F1D5D4C8208913C694EFDE036/
http://cloud-4.steampowered.com/ugc/506952824860418997/3E4A6ADB6253D7335673346CAEE9CEB87FC4138F/
http://cloud-2.steampowered.com/ugc/506952824860425537/8062565850788C8E7F2AC72609364E839E35F1F9/
http://cloud-2.steampowered.com/ugc/506952824860433923/53A2B3EF6CD65CFE9C7E5E49A19B51E9F8913BCF/
ninja edit:
as AvelC and Vannes187 posted in notes this could be caused by backpack getting into sight range i wanted to try it but i forget to take it off while testing, i had hunter one in those screenshots posted above but i remember i had much worse "screen streaks" few days back when im sure i was using the biggest backpack
as well while taking those screenshots above i tried to change the different graphic details and options including FOW without any effect