Possible Ahri Bugged Chat Interaction

I am not entirely sure if this is a bug with Ahri or another champion; but as I was playing team builder today, I noticed that when Ahri completed the full 3 casts of her ult while in vision, the number 3 appeared in chat in yellow lettering.

The first time it appeared I couldn't figure out what it was, but the chat info appeared additional times under the same circumstances.

This is the link to the game in question where it occurred http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1475266539/51120987

I will attempt to recreate the bug when I have time!

EDIT: When I asked the Ahri/Enemy team if it showed up in their chat they said no, but everyone on our team could see the yellow 3.