We have only had our QLED 55in tv since Christmas 2019 and it worked great for 4 months and then out of no where one day we turned on the TV and a 1 in. grouping of colored vertical lines appeared on the right half of the tv and then faded after being on for about 20 minutes. The tv had not been moved or damaged from the evening prior when it was last used. Now consistently every time we turn the tv on this vertical grouping of lines appear and then fades away after about 20 minutes of being on. The lines do not appear in ambient mode at all, however when using the Xbox, PlayStation, YouTube, netflix, or amazon prime tv, the lines appear and then disappear after 20 minutes of use. I contacted Samsung via chat and they advised me to do a reset procedure- didn't help at all. Very frustrating after spending so much money on a new tv and owning for less than 6 months!
Does this happen on all sources, inputs and the picture test? Also, does it happen if you don't have anything connected to the TV?