So I noticed something with Spitfire, Frost Gun and Zapper
Spitfire doesn't inflict the burn status on its basic attacks while Frost Gun and Zapper do inflict status (freeze for Frost Gun and shock with Zapper) on their 2nd or 3rd shot. Spitfire only inflicts burn on its charged attack.
Is it a bug?
it most likely is since they fixed it with zapper a while back but didn't fix spitfire
Doubt it will be fixed though