The line does not appear to have burned into the screen. It's just a
thin line of white light. Though you can see movement in the light, as
if the tv picture is still being shown on the thin horizontal line.

Though as the line is so thin, it's not possible to see any picture,
just the movement of the light.

Once the picture reappears after 10 minutes, there is no line visible.
The picture is normal.