There's still numberous ways. What I would do in this instance: Have the entire team group up & simply wait 40-70 seconds before going over there. As this guy watches his gunslinger run out twice without anyone to shoot. Then a couple go where he can see you, buy only long enough for him to pop it again. Within 2 mins he either runs out of orbs, or gets impatient and leaves bubble safety. I feel like you never even tried to think of a counter before declaring there isn't one.