I noticed myself the latest update is a little disappointing in terms of ambilight, in dark scenes on both Natural and Vivid mode before the light would go off completely in darker or black scenes which was great, but now in Vivid the light goes fully white in black scenes which is crazy, and the Natural mode glows a darker shade of white.
Game mode does make the image go fully black in darker scenes, but it also doesn't glow as bright for other colours, and is much faster and not right for watching movies with. A shame really, the ambilight worked better before they started fiddling with it. Anyone who also has an issue with this, my best advice is bringing it up to Philips, if enough people do they might sort it again.