Nautilus Ultimate Cooldown indicator inconsistent and wrong!

Just got out of a ranked game in which I was playing Nautilus with his new Warden skin, and mid game (after a team fight in which I used my ult) two of my teammates told me that the indicator-green-dot-thing was showing for them when the ability was still on cooldown. Another one of my teammates told me that he did NOT see it.

There seems to be some sort of inconsistency, I don't know why some would see it but others would not.