Zekes and Tahm passive

I just played a game as thresh supp vs tahm kench supp. I noticed during the match that when your hit by tahm and his passive is on you there is no timer on your de-buff bar telling you when his passive will wear off. Also i got Zekes during the game and i received no assists for having the effect on my allies. Only time i would get an assist was through the usual way of attacking an enemy or shielding an ally.