1. Pick Kunkka, level up Tidebringer and get Manta Style
2. Create illus of self
3. Check Tidebringer on the illus
4. Attack enemies with the illus

Result: Tidebringer is always on autocast for illus, so when they attack, it gets used, going on cooldown. However, since illus can neither make use of raw damage bonuses, nor can cleave, it does nothing but go on cooldown.

Expected: Since it is an active ability, only illusions which are allowed to use active skills (e.g. Hybrid illus) should be able to use Tidebringer. So it should be not on autocast by default for illusions.

As the ability was passive, illus always proccing Tidebringer was useful, as it helped making it less obvious that they are illus. But now that it's active, it makes it more obvious, since Kunkka can now use it whenever he wants, and not forced to use whenever off cooldown.