So I have a Radeon 450 (low-tier) 2016 15" MBP, and have been following the graphics debacle really closely. My system exhibits some of these issues, in weird ways. First of all: I never got full-screen distortions on the built-in display. I can't help with that. What would happen for me, is if I woke the computer from sleep or restarted while in lid-closed mode, with two external 4K displays attached, the graphics card would freak out, and the system would kernel panic and completely freeze. By "freak out", I mean I got either distortions on part of the screen, black screens, no signal, or a full screen random colour (I've had sky blue, dark blue, two shades of green, red... ), some times with a cursor in the top-left, sometimes without. No matter what, it would require a hard-reset to fix. Now, I installed 10.12.2 beta 5, hoping it would fix the issue. It didn't. Then 10.12.2 beta 6 was released today and lo and behold, it seemed to work! So I put my desk back together, and... the issue re-appeared. The only thing different was the SIDE I WAS PLUGGING IN THE DISPLAYS. Usually, I had the monitors plugged in on the LEFT side TB3 ports (esc-side). While doing the beta6 update, I turned the computer around so it could restart with the built-in display while updating, and tested with the monitors plugged in on the RIGHT side TB3 ports (TouchID-side). So I switched my cable routing around, and I have no issues with the displays plugged in on the right, now. The system sleeps and wakes fine, and reboots with the external monitors attached without issues. I know there were a few people in this forum that were having the same issue I was, and would love it if someone can corroborate that this also helps with their issue.