Whenever I go to paint in a full screen mode, if I have more than ~a handful of layers in a larger file (~100mb+), all the menus and tool panels flicker almost every time I make a brush stroke. It's unfortunately not quite consistent enough for me to give exact repro steps (I haven't figured out what triggers it besides full screen modes), though I've seen it happen in a wide variety of file sizes with different numbers of layers. This doesn't happen for me when I'm in a normal view with a floating or docked window, which is how I've had to work for a while. It's very distracting and makes working in full screen modes untenable.
I've observed this on my home and work Windows 10 machines. Both have good graphics cards, processors (i7) and at least 32gb RAM, both using Wacom Intuos tablets. I've tried mucking with the graphics card settings, but that doesn't seem to have any impact (even after restarting Photoshop).
I usually have the Brushes window open, displaying their stroke previews, the Brush Settings open, the Navigator, plus Info, Color, Properties, Layers, Actions, History (50 states), and Layer Comps. Dual 4K monitors. (also seen with 1x2k and 1x4k dual monitor setup).
I've been having this problem in Photoshop for at least the last 2 years.