[Gameplay} Thunderlord's decree not proccing

Seems like thunderlord's decree in not going to proc if there are at least 2 players with that mastery in the same team, it will prock for 1 of them but not for the other, it allways procs when im the only one with, it happened to me playing jayce and ahri, twice with ahri. I rly like that mastery and hope it gets fixed soon.