TheCoolDave I had some very similar issues with slightly different hardware. I noticed it when the white was at 100% i'd get weird pops of color-- sometimes frequently. Like you, I noticed that when I turned down the brightness on the backlight slightly, it resolved the flickering.
The funny thing is, and this should be unrelated: my phones LED screen was doing the same thing after a software update (and possibly after a low grade drop, but i don't remember). After the Android update i was never able to use the screen at full brightness again, or it would turn bright green and pop back to normal or bright purple. Lowering the brightness always resolved it.
I also had a responsiveness issue w/ lag when I was running a test on youtube. I made a crap ton of changes without documenting, but I think a full system reset fixed that. If any of my issues return or if I figure out what I changed, I'll def let you know