Let's look into this further. Can you send a private message here: http://bit.ly/2Kq3B5F with the full model and serial numbers of the television as well as any pictures that you have of the symptom experienced?
I am having the same issue with my 55" flat screen. It started as fine lines at the top and bottom and in the past week it has developed a 2 inch horizontal bar of discoloration at the top of the screen. The entire picture is becoming unfocused as well. Unfortunately, I'm 4 months past warranty. I have contacted Samsung customer service and was told "you should have called in sooner!" They kindly referred me to a local repair shop. I described the problem to them and was told the panel needed to be replaced......$850 + labor. When I bought this, I assumed I was getting a high quality product. The only thing worse than this TV is Samsung customer service. it seems that this is a well known issue. Samsung should stand by their product and take care of their customers.
@user49HgVUj6zq I'm sorry to hear that, do the lines still appear when you run a picture test. The steps to run it are, Settings > Support > Self Diagnosis > Picture Test, and then follow the on-screen directions.