I see why.
It probably thinks "if bullet hit barrel, than proc barrel explosion", and since multiple hit it, it's going to do multiple barrel explosions.
Match ID: 65998024 Timestamp: Started at exactly 02:42 and abused it for the rest of the game.
The abuser was fully aware of this 5x damage glitch. They intentionally rushed the Splitshot build extremely early (at 2 mins in) just to exploit this broken mechanic and instantly delete players, completely ruining the competitive integrity of the match.
Match ID: 66020308
Timestamp: not needed, they were doing it the entire game.
Person rushed splitshot as 2-3rd item and proceeded to bug abuse the entirety of the game, when called out on it, both them and their duo is playing innocent while obviously bug abusing to get kills. Both the holiday and pocket should be penalized or have their accounts suspended for knowingly bug abusing and playing with a bug abuser to get easy wins.