Diana passive bugged when using Guinsoo's Rageblade

I wanted to test out her potential damage with Guinsoo's Rageblade in practise and noticed that when fully stacked guinsoo's consumes her passive's 3rd attack with increased atk spd when doing her 2nd atk. It considers her atk spd buff as an on hit proc and consumes both her 2nd and 3rd atk spd increase during her 2nd atk. Its hard to explain but easily recognizable during practise mode. Was just wondering if someone from riot could look into the mechanic here and verify whether it was intended to interact this way.