Red horizontal line on my Samsung galaxy tab 3?

So, i have a samsung galaxy tab 3 and a 1-pixel wide horizontal line is showing on my screen.

First of all, i did not drop it, held it in wrong way, bend it… Just kept it normal
The line is just 1 pixel wide
When the screen is white, the line is red
when the screen is black, the line does not show
when the screen is blue, the line is black
when the screen is green, the line is also black
when the screen is red, the line doesn't show

I tried some dead pixel fixers from play store but didn't solve my problem:/
i thought someguy here could help so please answer if you got a solution

every answer appreciated:)
thanks in regards!

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