I purchased a Sony A8F OLED for ~$4000, the most expensive TV purchase I have made. I paid a premium because I expected a premium product and for the most part it's fantastic.
Unfortunately while watching movies and console games I noticed a fault on the screen, a large vertical band or smudge on the left side of the screen. It isn't always visible in bright or complex scenes, but it is visible with uniform blue, grey or green images such as a night sky or grassy football field and I find it extremely distracting.
After allowing about a year for the screen to achieve a uniform level I contacted Sony Technical Support with pictures as shown here:
https://i.imgur.com/h4GZfUK.jpg
https://i.imgur.com/xHdA1Qa.jpg
I circled the fault as the initial response from Sony Technical Support included the comment "I can't see the vertical line that you reported", I believe this was a lie intended to discourage me from continuing my Product Enquiry, however I continued the process.
After ~10 emails and further evidence provided in the form of more photos and videos, Sony Technical Support attempted to end the Product Enquiry with "After careful observation, our level 2 support agrees that the black band that you were referring to is not a defect. Please understand that Organic EL displays (OLED) are built with precision, but differences in brightness may cause slight lines or bands to appear on the screen. These bands become very visible in dark backgrounds. These TVs meet the suitable standards and the band is not a malfunction".
There was no elaboration or explanation of the 'suitable standards'.
I continued to pursue the Product Enquiry and eventually a Tech Support Rep visited to inspect the TV. After briefly viewing test and demo screens, the Rep determined that at normal viewing distances the fault is not visible.
I agree that during bright and colourful test and demo screens the fault is not visible, I didn't purchase the TV to watch test and demo screens, I purchased the TV to watch movies and console games, many of which have blue, grey or green images which render the fault absolutely visible at my normal viewing distance of ~3.2 metres.
The Tech Rep provided a written report when requested, which again provided no technical data regarding the fault, or elaboration or explanation of the 'suitable standards'.
The short version of this cautionary tale is: I spent $4000 on a premium TV expecting premium quality and service. I find the a TV which can't accurately reproduce an image of blue, grey or green to be unfit for its intended purpose.
Sony has replied to my Product Enquiry with various tactics ranging from obtuse/false (claiming not to see the fault), to delay/discourage (~10 emails to even schedule and inspection), to an appeal to authority (subjectively claiming there is no fault without any technical justification).
I am continuing the process now with Consumer Affairs Victoria.
I think waiting a year was probably a mistake; should have returned to place of purchase ASAP.
Hope you can get it resolved; I don't see how they can accept that there is a fault but its just not visible at 'normal' viewing distances!