OK, I did some quick and dirty, not-really-meant-to-be-accurate futzing with the second image in Picture Manager just to see what would happen to the lightsaber if I played around with the hue to make Luke's skin tone look warmer.

Notice that the saber is now a little closer towards cyan. Still more blue than in the other scene, but perhaps it looked a bit more green in that one shot originally. This tweak is not meant to approximate how the color actually looked, just trying to show that maybe the other shots look *too* blue because the rest of the color isn't warm enough.

So many mysteries...