Stalker 2, what is this anomaly (?)

There's certain spots that cause an effect similar to the bloodsucker screech when you stand in them. It appears harmless, you can walk in and out of it and stand it in forever with no effect. The mouse sensitivity goes down, the screen wobbles, there's a loud wind/garbled voices, and the screen turns bluish and distorted. I thought it might be psi-radiation, but it doesn't seem to actually do anything. I can't find anything on Google about this, what is this?