Two of the traits in the Engineer Firearms tree are bugged when they apply to the Elixir Gun skill.
Rifled Barrels is meant to increase the Elixir Gun skill range, and does, but also increases the duration of the conditions on some of the skills and decreases their cooldown. The Elixir F skill, for example, has a 5+ second cripple and swiftness buff with Rifled Barrels and less than 3.5 without. The cooldown is naturally 8 seconds, but drops to 5 with Rifled Barrels.
With Fireforged Trigger active, the normal cooldown drops to 6.5 seconds, but with both Fireforged and Rifled Barrels active, the cooldown remains at 5 seconds — the current default for Fireforged Trigger.
Cooldowns and condition durations change for other skills with Rifled Barrel active too. It actually increases for Super Elixir, and the durations for Tranq Dart go from ~1s Weakness and ~4s Bleeding to ~3s for both.
What the heck is going on with Rifled Barrels?