Is there any reason why Guinsoo doesn't work on Diana???

Even after stacking , Diana's passive is only applied once every three attacks. I remember it worked with the old OP Devourer enchant, as it did proc on every second attack, but since Guinsoo has been reworked, it doesn't interact with Diana's passive anymore.

Aatrox's W is triggered on every second attack, and pretty much EVERY other three hit passive in the game. Why is Diana excluded? I feel like this is the only thing holding on-hit Diana back as a decent pick.

I wanted to try out this build but got massively disappointed once i noticed it didn't interact with her Passive