[Disciple of Varastha] Audio bug on attack when focus equipped with Staff

With the "Instruments of Power" passive from the Disciple of Varashta ascendancy tree, equipping a focus with a staff causes a "blank attack" audio bug on certain spell casts.

Easily reproduced by casting "Lightning Bolt" or "Ember fusillade" with a staff and a focus equipped, though it surely affects others.

Not game breaking but annoying enough for people to avoid choosing this passive because of the audio degradation that comes with it.