Weapon Swap isn't instant in Demon Form

Context:
* Infernalist with Demon Form
* One set of weapons (a wand and a sceptre) is being used in both Weapon Sets
* Have Fireball and Living Bomb on set 1, Elemental Weakness curse on set 2
* Four spirit skills are active in both sets: Raging Spirits, Discipline, Siphon Elements, and Time of Need
* Elemental Invocation spirit skill and its usable spell are set to Set 1 only

When I'm in demon form and cast a spell that would change my set (casting Elemental Weakness while Set 1 is active or casting Fireball or Living Bomb while set 2 is happen), it doesn't happen instantly, there's a delay before casting the spell. If I tap the spell's button quickly enough, the set changes (observable via the Elemental Invocation buff icon appearing or disappearing) but the spell is not cast. This seems to indicate that the game is treating the "cast spell" action as a "change weapon set" action without actually casting the spell afterward.

This only happens in demon form. When casting spells of alternating sets in human form, the weapon swaps are instant as expected, and the casting happens smoothly and responsively.

Issue still present in 0.3.0b