Samsung QLED 4K TV QA50Q60AAKXXS Can’t Be Turned On

Hi guys, I’ve bought my Samsung 4K QLED Q60A TV last year and it’s only been 8 months old but I was told by samsung’s tv repairman that my panel has to be replaced. So he scheduled another appointment with me next week as he just came today to evaluate and assess my tv’s condition. For the past few days, the problem with my tv is that it can be turned on during the day but whenever I decided to turned it on at night around 10pm plus, the red led light just flashes twice and the tv screen keeps on flashing white non stop. It only worked if I turned it on again at around 1am or 1:30 am after around 2-3 mins the “QLED” logo will appear and there’s where I know that my tv can finally be turned on. Oh yeah, I forgot to add in that I do have horizontal black line on the mid bottom of my tv screen that tends to appear and re-appear every secs. Do you guys know what is the actual prob? is it really a panel issue? if yes, what causes it and is there any advice on how to prevent this issue from re-occurring in the future?