I'm sorry to hear that, does this occur on all sources? Also, does this occur during the picture test?
This has happened to me as well. I called Samsung and the only thing they will do is setup a service call that I have to pay for. I left LG to try Samsung and my LG is in another room, 8 years older and have never had any issues. I am disgusted because of how much I paid for my MU8000 and I see all these posts and Samsung is unwilling to fix this known issue!