High overall quality preset bug

[oblique juniper]

I found this small bug in singleplayer where, for some reason, when i have the high quality presets on, when i walk, some very small ugly black lines start appearing on my screen. but when im not doing anything they do not appear, is this on purpose?

it's kinda hard to see on my video but if you look closely.

I think it only happens on level 0

[trim flicker]

Anyone else experience this? Curious to see if its a hardware specific issue