On my first run of the game, I was in the final battle with Faba + Aether Employee alongside Hau. Faba was down to his last Pokemon, Bruxish, on low health. I had my full health Charjabug out and Hau had his full-health Primarina. Faba's Bruxish used Psychic Fangs on Charjabug and brought it down to half health and Hau's Primarina activated a Z-Move and used Hydro Vortex. There's one gigantic problem with this: Hau used his Z-Move on my Charjabug.
Is there an explanation to this? Is Z-Move AI bugged? Did it see that Bruxish resisted Hydro Vortex (despite it being able to KO) and instead went for the next available target? Is it because Sparkling Aria hits multiple foes and your ally is affected first in the spread move priority (as in if you used Earthquake in a double battle, your other Pokemon would faint before the opponent's?)? I'm almost to this same point in a Nuzlocke and I really don't want Hau to kill one of my 'Mons with a friendly fire Z-Move. Has anyone experienced this phenomenon as well, and does anyone have an explanation?