Thunderlord decree bug

playing as teemo against syndra.... syndra with 2 kills at mid game level 10 1 shotting me with ult, with 0 or just 1 ball stacked, what i see is thunderlord decree triggers just fromsyndra ult, without any other sspells or auto attacks from her, or any other champ.... it say thunderlord triggers after 3 spells or auto atacks.... why does it trigger from only her ultimate.... come on... and yes 1 shotting 1600hp with only ult without spheres stacked before even putting second point at her ult obviously cause she was level 10... and not just once this happed the whole game.... nerf her ult pls