Your TV has pink eye.
Could be a broken TCON-Board.
Trash. Not worth fixing
It's low on health
Try a different HDMI port or cable. If it follows, it may be the box.
Looks like magnet interference, but most (all?) modern tvs are magnetically shielded now. Try turning it on and off quickly 3x.
what can this be ?!
Chinese crap.
Backlight bleed. It's a cheap TV made from cheap components. If you still have a warranty, demand a replacement.