Limited Magic Resistance Animal

For a non-Bjornaer magus when would Limited Magic Resistance (Animal) be a liability?
Can it be considered a 'dump' flaw?
Normal mundane animal attacks don't affect any magical defenses, do they? What about Magical animals?

Actually, it is more of a liability for Bjornaer than other magi.

Attacks that can be resisted by Animal include CrAn spells that summon a medium to damage the target (projectiles made of anmal bone) or hinder them (Weaver's Trap of Webs), as well as magically conjured animals (Curse of the Ravenous Swarm). It also covers any transformed animal (Beast of Outlandish Size, Steed of Vengeance), including personal powers of supernatural animals that increase their combat capability (such as making their claws sharper or larger).

Where Bjornaer suffer more from the limited magic resistance is anytime they are in animal shape. Then, any PeAn spell cast at them has a much easier time penetrating their Parma.

So no, I wouldn't consider it a dump flaw for a Bjornaer magus.

No I meant that it would be an ok flaw for a Bjornaer since they are actually animal when in Heartbeast form, but now it is one of my players designing a normal human Tytalus that has no interest at all in shapechanging and the art of Animal. Then I was trying to find ways where I could use it against him but it seems rather limited so I think I will not allow it.

Sorry, read your original question quickly and missed the "non" Bjornaer.

Still, Animal is a physical medium that spells can use to do damage. Much like Aquam, Auram and Herbam. So I'd allow it and simply find ways to attack him with something related to Animal.

Now, if he were to take Limited Magic Resistance in Imaginem... that would be closer to a "dump" flaw. But even there, just have someone scry upon him. Or blind him using an Imaginem spell.

Just had a thought. How would the flaw impact Certamen? I'd say it means that if the magus uses the Form for Defense, it counts as 0.

In short, if someone takes the flaw, it is up to the storyguide to make sure it is a flaw. Not too often, but at least occasionally when it matters.