I get brightness flickering while I'm on my Desktop (Not playing a game). When I notice it, I would check the refresh rate on my panel and see that it's bouncing all over the place. The only I way to solve it temporarily, before it eventually comes back again, was to hit SHIFT+CTRL+WINDOWKEY+B to restart the GPU driver. I can turn of Freesync and that would fix the issue as well, but that isn't a proper solution.
Has this been occurring for anyone else? If so, have you figured out a more permanent solution?