This TV must have cost a lot of money.
I know that in the UK manufactures get away with the 12 month warranty,(despite the EU directive that it should be 24 months). We were told that the UK did not sign up to this as we are better protected by such legislation as the sale of goods act.
I have no idea is this is a known fault, but a fault it certainly is. Perhaps you should obtain advice as to the protection the law gives you, to have it repaired free.