What are Taliyahs stun mechanics?

"Taliyah causes the ground to rise under the enemy with the most Mana"

Is this most total mana? Most current mana? Most mana percentage? I'm inclined to think the latter since 8/10 stuns in the last game hit my Kogmaw even though other units had a higher mana number. Some clarification on this unclear tool tip would be nice, there's already enough RNG in the game, let's get clarity on things that are supposed to have mechanics.

Edit: this is what I found on a website - in game says random enemy. Anyone know when this was changed?