Spells: Ice Giants and Wiz Spell "Rend"

[Xersius]

Ran into an interesting potential bug today. Decided now that I'm 49 I'd check out Ice Giants outside of Permafrost for nostalgic purposes. Looked at my spells, decided to try Ice Comet... resisted. No surprises here as they are ice giants. Rooted it with no issues, and loaded the magic DD 'Rend'. Resisted Rend. Tried again... resisted Rend. Casted six more times and resisted Rend.

Now Rend is a magic based spell, so I have no idea why a blue con mob that Root/Snare lands on would be fully immune to Rend.

Conflagration works fine on them/works from a distance.

Is this a bug in the code?

Sarpidon