Playing a necro, depending on the surroundings and spell used, green lines are flashing from the top of the screen.
I am a bit unsure if this has been reported(not too easy to decode all reports), so here goes.
It appears to happen mostly in canyons where there is some kind of light above. And it was really bad casting wandering spirits in a cave in early game. The color matches the wandering spirit one pretty nicely. Back then I swapped spell and the problem disappeared.
A brief video showing it in action, it can be much worse than this. Also some red similar stuff has happened in a time zone near Rust Lands imperial. All used are minions with no damage conversion/additions (physical).
My rig:
GeForce RTX 2070
Driver currently 445.87 but it was the same with an older driver.
AMD Ryzen Core 7 2700X
16GB RAM
2560-x1440, 144Hz.
Very High graphics setting