drmrbrewer wrote:
Having said that I thought the "light on dark" band might have gone, it is really back with a vengeance... the brightness of the band rapidly changes too, flickering horribly to the point where the device is almost unusable. Oddly though, this light-on-dark band doesn't seem to appear at all on a mid-grey or even light-grey background... it may only appear over a pure black background.
You've proven that the laptop has a hardware issue with the Display Assembly. It is either a bad cable or bad LCD Panel....either way it requires having the whole Display Assembly replaced.
The vertical band will be more or less visible depending on the background color beneath the band. I've never seen it behave as it does in your pictures though as the band is not visible even though the same color is present in multiple places. Maybe a tech can try reseating the display cable to the Logic Board just in case it is a bit loose, but I doubt it. Very odd.
By any chance was this laptop's Display Assembly ever replaced before, or had any other repairs to the laptop? I have seen an Apple Display Assembly act very weird when it was not calibrated & paired to the Logic Board. Very disconcerting that is required or could change how the display works to such an extent (ghosted images & odd images....don't recall all of the details).
I guess you could also try a DFU Firmware Revive which resets the security enclave & system firmware. I doubt it will do anything here though, but may be worth a try. These 2018+ Macs are very odd beasts which make very little sense.
Please let us know what happens when you have Apple or an Apple Authorized Service Provider examine your laptop.
