Maybe it didn't do 1 damage and instead did 0 damage.
Some spells (the paladin stuns) could be fully resisted but still actually PUSH the mob the way you were facing, could be one of those things, if there was a secondary affect on the spell it could trigger but do no damage.
Effect 1 = Dmg
Effect 2 = stun
Effect 3 = push +5 yards
etc..
|