Powder Keg and Xayah Passiv (Bug)

I just finished a game as Xayah and found a game-breaking bug. In my opposing team were a Gangplank and i wasn't able to kill his Powder Kegs when i had my passive feathers up. Gangplank noticed it as well and after asking he did some Kegs in the middle lane. So i tried multiple times killing Kegs with my passive up and some with only a „normal“ auto-attack Every time i auto-attacked with my passive up i couldn't kill a single Keg. When auto-attacking normally without my passive i could kill the kegs all the time. Both of the time Gangplank let me kill his Kegs for free because he was just as curious as i were. As Xayah i have my passive up in most of the fights so it could be really game-breaking not be able to kill a Powder Keg in the right situation.