Flame Blade

Observation: Despite the description, the main portion of Flame Blade damage (base + wisdom modifier) seems to effect some monsters immune to fire. For example, against Blackbone Skeletons they recieve the main damage but are immune to the other effects (Flaming, Flaming Burst). Againt the Avatar of Juiblex, this also happens: it recieves the main damage but is healed by the other effects. Don't know if this is WAI.