Blue Voidborn's existence regarding the new lore

There was quite the debate about the Voidborn that Ryze destroyed in Call of Power, about if it was a Watcher or not and Riot confirmed that it wasn't, but I can't seem to find a reason for this voidborn to be blue now. Before Liss and Velkoz's update my personal cannon was that that voidborn was born from a Frozen Watcher, an ice-adapted Watcher... But that no longer works.

We can see in the picture that comes with Liss' short story that the Watchers entombed in ice have purple eyes, what isn't weird considering that they are normal watchers trapped in ice, but when a purple Voidborn is born from Olar's corpse, i can't seem to find a reason for Ryze's voidborn to have blue eyes anymore.

At this point I assume that its an error from the video, or maybe the ice is thick enough to turn purple into blue, but i'm not sure anymore and it's quite intriging for me, as it might be some data I'm missing, or even another subspecies of voidborn that no one but Ryze has seen thus far. Could anyone enlighten me in this matter?