Morde gameplay bug

Mordekaiser’s passive = hitting an enemy champion with basic attacks or abilities 3 times will trigger the ring.

I noticed this in the practice tool. I use E on the dummy then auto attack and I get the ring. I only used two attacks on an enemy champion and I got the passive proc. Same thing with Q. Q + auto attack procs the passive instantly.

What is with this 3 hit when I’m getting the passive in 2 hits?