Gangplank bug on 6.3

Hello, i think there is a bug on on 6.3, when i put a barrel and a second beside the first in a creep wave or champion ( teamfight ), sometimes when i q the first barrel ( to explode the second), my q is redirected on a creep or a champion. In the beginning, i thought that i missclicked but i checked in custom game with a friend. Like i said, this is sometimes but it can be gamebreaker.

Thank you for reading and sorry for my english !