I'm getting the same sort of issues on nvidia but in singleplayer. Some observations I've made in my own findings:
Only happens to me in very POI dense areas, like city blocks that all have POI's (no blank/forested city blocks).
Can easily be replicated on NitroGen maps (due to increased POI density, I wager)
Seems to only be per POI - either it bugs and has the phantom blocks or it doesn't. I often see a POI with Phantoms Blocks and then one right next to it that's just fine.
No graphic settings seem to increase or decrease the rate at which they show up.
As others have said, exiting the game and reloading in front of the affected POI works, though it's a bit time consuming, obviously.
I only started having the issue this past Tuesday. No system changes to my PC prior to it starting.
Now that it's happening, I updated a nvidia driver and my Windows, but neither had any impact (positive or negative)
Just figured I'd throw some more info out there and see if that helps anyone figure this out!