The tooltip for Acid Flask - Toxic Salvo specialization states
You now throw 3 Acid Flasks in a line, but Acid Flask costs more mana.
Extra Flasks: +2
Manage Cost: +5
It does not mention an increase in cooldown time. However, after putting a point in Toxic Salvo, the cooldown goes for 2 seconds to 6.
I don’t know if this is intended and the tooltip just needs to be updated to indicate, or the increased cooldown needs to be removed.