Dysfunctional Rules IX: 1d3 Dysfunctions from the 8th Level List

[Hellpyre]

This ability adds an energy descriptor to magic missile, but doesn't actually change the kind of damage dealt. It just says resistances and vulnerabilities apply. So, it's not Fire damage, it's Force Damage But Fire Resistance Counts.

Although still a force spell, any magic missile altered in this way deals additional damage against vulnerable creatures and less damage against creatures with related resistances and immunities.

It's pretty clearly intended behavior. I mean, it's super weird, but I wouldn't say it was dysfunctional.