I think what is happening here is that we see demographics of device configs that Apple purposely distributes components differently. There have been instances in the past where Apple did the following across the same model:
- use SanDisk-only flash controllers and memory on entry-level MBAs
- use both SanDisk or Samsung flash controllers and memory on midrange MBAs
- use Samsung-only flash controllers and memory on max-storage models of MBA
I believe (read: not know) that we are probably getting less cases of people not being able to reproduce it because I suspect that the better display panels (Apple is known to use multiple suppliers because they had a lot of production issues in the past where products could simply not get assembled because of one key component; plus it's cheaper) are locked in the higher-tier configs (Cellular, 256, maybe both). This is the reason why you can't find a model in an Apple Store not showing this behavior.
While it is not essentially the same model, I was able to reproduce it mildly on an iPad mini 4 WiFi but my iPad mini 5 256 GB Cellular does not have it, not even in the slightest and not even with SloMo videos looking for it.
Can people here seeing or not seeing the issue confirm as to which model they have?