Illaoi spirit bug
I noticed in a game against illaoi that she got a spirit pull that pulled the spirit into her fountain.. The fountain laser killed the spirit and the person did not become a vassal .
Also the person did not take the damage % that the laser did to the spirit.
This happened 2 times in a row so i bet it is repeatable.. And if it had worked properly it would have given their team a chance to repel us which could have effected the game. Unlikely but possible