[Samsung Galaxy S8 ROMs, Kernels, Recoveries, & Oth] partcyborg:
Welp, I figured it out.

The problem is with the always on display, and unfortunately the only fix is to turn it off it seems. I was half right it turns out it was just the other way around.

The bug is caused by a race condition in the display driver which is likely part of boot.img itself. What is happening is when the screen turns off and aod is enabled, after a short time the phone begins to initialize aod mode. When it does that, it changes the display mode somehow and drops the screen into some kind of ultra low power mode so that you don't eat your battery like normal SOT. the race condition/bug is that there is a VERY small window (we are likely talking tens milliseconds max) where the device puts the screen into low power mode but has not fully initialized aod mode and completed the necessary setup. IF during those precious few ms you happen to press the power key or otherwise wake up the device, it blissfully obeys but since the aod mode had hot finished setup it just turns on without switching back to normal display mode first.

What you are seeing with the green/garbled display is the device displaying the system and other normal functions while still in ultra low power mode.

As the ultra low power mode can't handle fast moving things and does not have then energy to display white backgrounds in settings and other menus, it lags a lot through dropping frames (slow) and gets distorted not being able to power the panel propey (green).

To be frank my guess is this bug has something to do with being in permissive mode, where some usually blocked sytem call or command succeeds which triggers the race as opposed to being blocked on raw stock as tmits enforced. My guess is that the s8+ has more work to do in terms of shifting power so around so the "gap" time exposed to the race is longer, which is why s8+ sees this so much more often than the s8.

Consequently, it's why the initial aqi1 boot.img and eventual performance package listed exhibit it less. The new kernel and largely stock driver systems perform better, with obvious improvements in the graphic displays. This serves to minimize the "vulnerable" time even further, making it harder to hit the sweet spot.

I'm going to go (mainly out of pure curiosity) see if I can find the specific syscall/app/action that triggers the race inside logcat. If I find it and can somehow block it, great I'll update the thread. Otherwise, my apologies if you felt or feel misleaded. I had to try really really hard to actually cause this to happen and have lived in day 2 day life for like a month at least without experiencing this naturally with this from with aod on sometimes and off others.

To be clear: the ONLY way as of now to completely 100% remove the chance of the aforementioned screen issue is to turn off aod. I absolutely can not make it happen with aod off and stand by that statement (for the s8 anyway).

I will update the op with this info and altert the subject and title to reflect how screen 100% fix is obtained. I still feel strongly that flashing this package is the best thing for your rooted phone to come through in a while, as the display looks so good now i use my phone for everyrhing. Watching 4k HDR videos today almost brought me to years (lol not literally but holy crap!).