no one saw any kind of flicker, stutter
PWM "flickering" isn't normal flickering like you can easily see from a flourescent light bulb or CRT screen. Those things flicker at 60hz- easy to see.
The PWM flickering frequency used on iPhone OLED screens is 4X higher (faster) at 240Hz. If you hold the screen still and stare at it without moving your eyes or scrolling, the rapid ON/OFF flickering of the LED pixels can't be detected.
But for those of you who claim not to be able to see it (the flickering PWM strobe light effect) there's an easy way to REALLY see it.
Here's how:
In a dark room or outside when it's dark, set the screen brightness of an iPhone OLED screen to 50% brightness or lower. For this test, the lower the better (to see the flickering).
Launch the Notes app and open a blank note so that the screen is showing all white.
With a good grip on the phone (so you don't drop it) stare off into the distance at some distant point and keep your eyes steady. Don't look directly at the phone and don't move your eyes.
Now swing the iPhone (held tight in your hand) quickly in front of your field of vision but continue to stare forward in the distance- not moving your eyes.
The faster you move the iPhone, the easier it is to see the flickering.
As the iPhone screen swings back & forth across your field of view, pay attention to what it's doing in your peripheral vision. You're not looking at it but noticing it.
You'll CLEARLY see the strobe light effect of PWM as the screen flickers on & off while the phone is moving.
Granted, nobody uses an iPhone by swinging it in front of their eyes, BUT every time you move your eyes while staring at it normally, (looking at pics, reading text) the same effect happens since your eyes move very quickly. It's very subtle, but for those of us with highly perceptive vision- the strobing is very bothersome and soon becomes fatiguing and painful.
Unfortunately... Once you become aware of PWM flickering- you can't not see it ever again- you'll always notice it to some degree.
If the "swing an iPhone in the dark" test is done with an LCD iPhone, the light from the screen will become just a blurred line of light as the phone swings by instead of a flashing beacon