I don't know if this is by design or a bug.

Serpent strike with a sword with a hunter fires the Maran weapon extra fire attack.

Serpent strike with any other weapon, staff, spear, dagger, whip, do not prog it, ever. I am making an assumption axe would fire it, but hunters don't know axe so cannot confirm.

This is strange and wanted to ask about it to see if they should be brought in line or if its a rogue piece of code for serpent strikes with non-normal ranger weapons.

You wield a jagged silver kris.

You dart in quickly past an immortal servant's defenses with the speed of a snake!
Brilliant silvery flame erupts along the blade of a jagged silver kris as you drive it deeply into an immortal servant!
Your flaming bite === INCINERATES === an immortal servant!
Your serpent strike MUTILATES an immortal servant!