Hello everyone,
after long discussions with apple support and some thoughts on my part, here is the conclusion.
to begin with, there were two manufacturers who shared the contract for the production of new screens on the iphone 12 pro and 12 pro max one of them signed for the first time this year with apple, the second is that They have been providing apple screens for a long time ...
most of the screens were provided by this new company, probably following a more interesting offer.
But a much less interesting quality!
For my part, I actually returned my unit for a replacement on 12/08/2020. (no problem for that)
Initially I was to receive my replacement unit on 01/04/2021 (I had noted two days before the return request that if I ordered a new device it was the same delivery date)
Later on 12/13/2020 I notice that the delivery date is brought forward to 12/28/2020 and indeed the date for a new device in the apple store is also advanced.
I will therefore receive my device at the same time as if I bought a new one!
whereas if I precede a replacement I am in VIP treatment to receive a new unit as quickly as possible (this is real and lived and confirmed by the apple team)
The conclusion is that a new production line has been opened to design flawless units.
The rest of the defective units are no longer delivered.
No updates will fix the problem!
as explained very well @ m4x1k
(for my part, in addition to the screen twinkling I had lighter lines and spots on my screen, this indicates a poor screen quality)
Return your devices as soon as possible before it is too late, from now on you should receive a faultless unit if it arrives by 12/28/2020 at the earliest.
!!!! I am a European resident located in Belgium !!!!
NB: at the time I make this publication if I order a new unit I will receive it on 01/06/2021