Bump. Can confirm its still present as of jan 20 2025. Melee part seems to be fixed though, its within reasonable and intuitive limit of ~180 degrees in front of you if you punch it in air (press barrel skill as you are jumping, additionally double jumping for even easier control).
The first attached video demonstrates the bug and also potentially a new part of it: you can cause it to explode in place, although I cant replicate it reliably, nor is controlling the direction close to intuitive.
Moving the camera smoother and slower (akin to air strafing) does seem to make it easier, but its still unreliable and it could just be placebo due to the familiarity with air strafing, included a comparison of attempts in the second video(sending barrels at the bounce pad at different angles to show the baseline bounce trajectory deviation->moving camera fast->moving it smoother->moving the character with the camera similar to air strafing).
But this last part is mostly to say that this is not in a state that it can be a feature of Holliday's kit, if you want to keep it in the game, the behavior of this should be consistent. As it is right now, it's only griefing people who do this unintentionally and doesnt provide any skill demonstration freedom that I often see in valve games as bugs get turned into fun gameplay features.
The last video is a demonstration of what seems to be the most consistent way for ME to do this. When sending barrels backward I am holding both forward and backward keys. I am not confident what action I'm doing specifically that causes this bug.