Gangplank Barrels can stop Gragas' Body Slam (E)

Title says it all. Played against a Gangplank as Gragas, every time I would use Body Slam he would put a barrel down right in front of me. This is an extremely easy "bug" to recreate.

It seems like a "bug," as to my understanding Gangplank barrels do not have collision? If they are supposed to have collision, it feels like a very bad interaction that can be abused much more easily than it should be.

This is very reminiscent of S1 where you could put wards down to stop Gragas E/Rammus Q/Blitzcrank Q etc.