Patch 4.18: Sion Rework Bug (Roar of the Slayer) [Gameplay]

Bug Description: When using "Roar of the Slayer" on a monster, there is a point during the animation where the target becomes invulnerable. This was tested with "Smite" and during the knock-back phase of the skill, the monster went invulnerable and the damage from "Smite" did not apply. I was able to recreate this several times on different monsters by activating "Roar of the Slayer" and as soon as the monster begins to move from the knock-back, to activate "Smite".

1. Activate "Roar of the Slayer" while targeting a jungle monster (untested if it works on minions as well);
2. As soon as the knock-back applies, activate "Smite" on the targeted jungle monster. An "Invulnerable" message should appear.