ToME: the Tales of Maj'Eyal

When I look at the description of Equilibrium, Equilibrium seems only effects the Wild Gifts types.

But some of my SPELLS failed when I had high Equilibrium.

They use Equilibrium but they are SPELLS.

Is it a bug or Equilibrium actually effects any talents using it?

It affects any ability using it as a resource. And a spell using it is a nature/magic hybrid (I assume you're playing Stone Warden)

They are categorized as spells to show that Zigur still wants to murder-eviscerate you for using the natural resource that is mana.

But you're powers still rely on using your hippy-like bond with nature.
So nature can still give you the cold shoulder for making it pay for everything and not giving it enough attention.