[Gameplay] Zilean's Passive has a significant bug.
So when your playing Zilean and your passive is usable on an ally, if they are moving away from you, it is incredibly difficult to get Zilean to activate his passive.
He will bug out and stop following the ally with no action - this occurs sometimes when your well within the range of the passive.
Sometimes it takes me over 5 right clicks to get him to start tethering to an ally to level them up.