Another (rather peculiar) issue has cropped up with this set. Every once in a great while (only happened twice so far) the screen will go straight black and white (no grayscale, full stop two-tone black and white!) and lock. Sound and functions still work, but you can't see the menu or anything other than the frozen B&W image. The only way to reset the TV is to power it off and back on again. The image remains on the screen until the color wheel shuts off upon power-down. Very odd.
EDIT: It just did it again. Snapped a crappy photo of the screen with my phone: