Finished the fight in the Temple of the One. The non host player won. After that if the non host left the room the host screen went black. If the host and non host became separated too far the hosts screen tried to follow the non hosts characters. Saving and reloading fixed this.
Players standing on platforms high over the non-players head were hit with the Whirlwind skill.
The Hail Strike skill gives three target circles, but seems to rotate randomly after confirmation, so they are still centered at the same point but the actual strikes happen in other spots.