Commonly when you clearly hit a vault with Virulent Bound you don't innitiate it. I believe this happens more often when not at an completely straight angle towards a windows for example, even at a slight angle it can fail on a direct hit.

I would assume that vault detection falls under the environment collider, i would suggest giving it to the survivor collider and increasing its value. Or giving it its own collider if that's not already the case. This might also be connected to the environment collider being to low on the ground and not hitting the vault and istead a wall or the floor for example.