Zephyron , most players use CSTN screens which are a sub-catergory of LCDs. LCDs are very sensitive to temperature.
The way CSTN/LCD works is, when it is powered down (off), beneath the screen, the crystals are solid. When it is on, depending on the input, the crystals are heated up to change from solid to liquid, and produces the colours.
When you left it in a very cold room, even when you on the player, it does not produce enough heat around the whole screen. Thus some stripes appear, as they are still in solid state.
While in a heated room, the crystals change easily from solid to liquid.
This could be what you are experiencing.
Hope this helps..
