Black splotches flashing in full screen mode

Long-time user of Scrivener for Mac. Have always written in full-screen mode. After updating to Scrivener 2.8, I’m getting flashes of black splotches when I write in full-screen mode. They are random in how they appear, sometimes a long thing line, other times rectangles and squares. Anyone else having this issue?

OS is Sierra 10.12.

Thanks.