Zombie Nunu's passive colour.

So I brought Zombie Nunu today and notice that it still kept default nunu's passive colour, which looked extremely abstract from the skin, however after doing some light research I came across this thread: https://boards.na.leagueoflegends.com/en/c/skin-champion-concepts/z9pJLjwh-could-we-change-zombies-nunu-passive-color

This thread implies that the passive colour was changed to green about 2 years ago, but for some reason, the passive colour is still blue on the live servers. Was it reverted? Why ?