The description of Arcane Resonance has a magnitude placeholder which makes people believe that the blindness effect scales with their power. However, due to the implementation of the spell it has always magnitude 20 in practice. The spell place an object (the noise generator) at the target location and, when dualcasting, also an "explosion" which applies the blindness effect to nearby actors. Due to this construction, the blindness effect is not caused by the caster, but by the explosion effect instead. This (maybe sub-optimal) construction means the caster's magnitude modifiers are not applied to the blindness effect and it has the base magnitude instead.
Arcane Resonance is redesigned such that the blindness effect scales with power. If not feasible, the description needs to have a hardcoded magnitude value instead.