Try factory resets and check for new firmware at samsung.com.
Sadly any panel issue unless under warranty means you should not repair this.
Model # UN55h6203
For the past few months, we have noticed a shadow across the top of the display, especially during light or outdoor/daytime scenes. I have adjusted and reset the picture but it persists. Especially when it has been on a few hours. This was purchased brand new 2 years ago last March.
Any helpful input appreciated.

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