Flashing Vertical Bar of Coloured lines when white background

Have a Samsung QLED QA65QFNAWXXY 2018 TV -

Started showing a fast flashing on/off Vertical Bar of Vertical Coloured Lines in the same place ..in the last third of the right hand side of the screen....but at the moment only occurs when the background is white and starts after the TV has been on for a few minutes.

Anyone have thoughts on what this likely could be - LCD Panel ?....T-con Board? ..... Main Board ? - Dirty Connectors? Thanks in Advance!

Still photo of flashing bar of coloured lines Samsung Tv - showing up when there is mostly a white background