The Phantom Cubic and the Hex Cubic of my SK lvl 86 are just sitting there and looking pretty. I watched them closely during PVE hunting for 2 hours and they didn't shoot a single time.
Quite different from the old 3rd class cubics, which I kept. They are alive and react as soon as the attack starts, which I consider as "working as intended".
Haven't tried the new ones on longer fights though. But for normal hunting they are useless atm.