Cool thanks for info on that tool. Mine is MG8P3 it says. But yeah as I posted elsewhere think all OLED suffer from this it's just that most don't notice it since only really noticeable in shadows or near total black which not as noticeable on IPS due to IPS glow near dark. Also remember all phone OLED have 2x as many green pixels so also more noticeable at lower light levels. Normally software used to turn down brightness on green pixels because of this but guess Apple needs to tweak or update algorithm they use to mask extra green like all other OLED phones do including every other iPhone OLED. That's why you're also hearing some iPhone 11 owners noticing green tint on their phones too since Apple must've made change in recent iOS update to change how OLED pixels work at low light levels.
Only other OLED phone I got is the LG V35 and it also has the green tint issue never noticed it before though till I got my iPhone 12 to compare. Seems Apple might be using LG OLED again in some of their iPhone 12 displays though don't know how to tell. Would explain the green tint issues since LG has had issues since back 2017 when my LG V35 came out!
This of course does not explain the quality issues with LG's pOLED displays, especially as LG does manage to produce excellent pOLED displays for Apple's Watch. It
https://www.oled-info.com/burn-vs-image-retention-and-lgs-new-p-oled-displays
Actually just took a pic of my iPhone 12 on tripod in this pic along with iPad with IPS display and iPhone SE 2020 also with IPS display below it all in front of my 43" PC IPS display.
They all show green the darker the squares get so seems like it might actually be normal. The thing with the IPS displays is that it's not as noticeable since the IPS glow mixes with the darker blocks as you can see in pic.
https://postimg.cc/G9kVJ9ht
Also, if you screen looks to yellow probably got true tone or nightshift on since here's a pic of the iPad before I forgot to turn it off and you can see how colors shift to yellow!
https://postimg.cc/7fwpXR9S
Seems didn't win panel lottery all my displays got manufacturing defects :( Still doesn't explain why my IPS displays also show green tints in darker area since they don't use 2x the green pixels the OLED screen do?
Seems Apple not using same manufacter to make iPhone 12 displays or maybe very large batch of bad panels where stencils not lined up correctly on OLED display as excellently explained in this article:
If you ask why devices from Samsung or Apple or others do not have display tints, it’s probably because the manufacturing process used in those OLED panels are either different (there are other ways of manufacturing OLED displays too like Color Filtering or using Electron Beams) or the method being used is more precise which cancels out any human error.
https://techpp.com/2020/08/06/oneplus-nord-amoled-green-tint/
Anyways, as my pics show seems all panels have problem just more noticeable on OLED due to better contrast ratio. Guessing Apple will release an update to reduce output of green on OLED displays to make it less noticeable since that seems to be what Google, Samsung and Apple have done in the past since seems to be recurring issue!
Green tint: A familiar issue
https://tech.hindustantimes.com/mobile/news/iphone-users-report-a-green-tint-on-display-unclear-what-s-causing-it-71591503939834.html