Caitlyn's Basic Attack dealing damage to target before bullet hits

I have no video nor pictures about this. [sorry I don't speak fluent english and will try my best to make it clear xox <3]

I just played Caitlyn for the first time in weeks in Summoner's Rift, Normal (non-ranked). After a few minutes of playing I noticed my **passive ** showed ready **before **I attacked. Not being used to Cait, I thought I had just forgotten how it worked, so I kept it going (anyway, I wouldn't leave...)

But when I looked at my damage on minions, I noticed the damage sometime showed (and was dealt to my target) before bullet even went out of my weapon. This was resulting in some bullets hitting minions disappearing bodies - they were dead 0,14 second before bullet arrived.

I tried to understand what was wrong - Was, even, something wrong? - and I first thought it was the Red Buff who would make that happen, but it happened at anytime, with or without Red. I don't remember seeing this happen on a non-critical-hit basic attack (but I wouldn't swear... I was trying to focus on match as well, you know... them adc's...)

Another bug about Passives + Critical strikes? Except this, which I think is a bug, I thought (maybe I was wrong) that my passive (150% dmg to champs; 250% to minions) could NOT add critical damage? Am I wrong? I had around 300 Attack damage and could deal some** 1300's** on minions/monsters when my passive was up, but sometimes only did 700-800 (when, 59% of the time, I wasn't critical-hitting). I had Infinity Edge as first item. Anyway, my mathematics abilities tell me 1200-1300 is more like 400% of my Attack Damage. But as I said : Maybe I was wrong...

Finally: Has anyone seen this bug on Caitlyn's basic attack too?

I hope this will help solve the bug. And if it's not a bug, well sorry for my nubism rito <3 If Riot team has questions, feel free to message me.

enjoi