HI all,
Please see notes here:
http://www.tski.co.jp/baldio/patch/20011107.html
The "light blue" con was not added until almost a year after Velious (right around when luclin was released, I think slightly before).
Those mobs which con light blue currently should still be worth xp while they con green however (but the player would not know the difference between those greens and light blues until killing one).