Got these black polygons on my screen, per these images: http://imgur.com/a/2koCZ
They’d tend to radiate out from a point centered somewhere in my view, and would move about if I turned+moved. They did not appear to be tied to any particular objects (like the bus stop bug in Chapel that was fixed a couple months ago).
The issue persisted across a couple maps, albeit only on one server. It resolved itself by the fourth round on the server it’d appeared on.
Win 8.1, i7-3820, AMD Radeon HD 7950, 64 GB RAM