weird looking Diana visual bug?

I'm posting this in Gameplay because i don't know if it counts as a real Bug

cut to the chase, i noticed something very odd while i watched this video, and it kept bugging me so i went back to investigate

if you look very closely (around 1:08 where my link should start) he's showing off Diana's passive, and lets you see what the "im gonna hit you" glow VFX looks like -- but, right before he actually attacks, the 3 hit buff wears off on Diana, check her buff bar

the visual passive attack effect still plays, but it does regular damage as the video plays, the numbers are normal, but it looks like Diana is proc'ing her passive one attack earlier

it had me really confused until i went back and looked at it closely

it plays like : hit - hit - fake passive - hit - real passive