Checking the back weather data, both KL and Penang were essentially calm and partly cloudy all night during the hours when this flight could possibly have been returning in that direction. Broken cloud layers were reported at or near 3000 ft. From what I recall of the satellite imagery (but I was then concentrating on areas further north) there were tropical thunderstorms quite a bit further south (probably south of Singapore) but as usual in this part of the world, dissipating and remnants drifting west. I think we could rule out weather as any kind of a factor in this event, even some theoretical last stage return to base.