happens on all inputs , trouble shooted everything that was recommended, faulty backlight no doubt , that sounds like manufacturing/ assemble/quality/design problem. under 2 yrs old. disappointed long time customer. good luck with me Samsung your worst nightmare. new tv voucher equal too i dont want it serviced this is a hassle and waste of my time. but whatever it takes it takes i will call everyday until im satisfied. the comments on here are appalling. Samsung should want happy satisfied customers, its not our problem your product is faulty. billion dollar corporation . obviously theres problem on your end . i dont got another 700 hundred dollars to spend, when my last one :model 5: i think is still working fine. my name isNick Smith i will continue this rant tomorrow with yall.
You have been affected by the typical dark vertical shadowing defect that is present on samsung budget - mid range LCD tvs from 2016 - onwards. It's extremely common and generally happens between 12-18 months of the tv's lifecycle.
Unfortunately it requires a full screen replacement. However, even if it is replaced, it will likely fail again in 12-18 months as it is a defect rather than a per panel problem.
here is a link to how common this problem is