Since you've disabled Gangplank, you should try to work on his Powder Keg bugs.

There are quite a few.

I had my Kegs refusing to blow up no matter how hard me and my enemies auto attacked it. Literally Invincible Kegs. HOWEVER, I could still use them for Multiple chain explosions as they wouldn't dissapear when doing so (but still deal damage). This is what I could consider a Major bug and the most frequent one.

I had a bug in which Chained Powder Kegs weren't critting despite the Main one doing so.

And I had a bug in which a wave of enemy minions somehow got aggro of the Keg and blew it up, giving me the wave gold lol.

Oh, and I've also seen allies being able to auto attack my Powder Kegs, tho this isn't as big as the other ones mentioned above as they couldn't reduce it's health at all.