[Gameplay] Summoner Dash Making People in Camille Ultimate Untargetable

I played a game of Legend of the Poro King as Camille, and the enemy Hecarim Marked one of my allies with the summoner spell, then used Dash to dash to them after being ulted by me with the enemy being outside of my ult range. He was then untargetable for the next 5 seconds as if he were still in the Dash. Video included.

https://www.youtube.com/watch?v=fV0vh880Hu8

How to reproduce: On Legend of the Poro King or ARAM, after being targeted by an enemy Camille's ultimate, use Summoner Mark/Dash to dash to an enemy outside of the range of the Camille's ultimate. You should hit Camille's wall and then remain untargetable as if you were in the Dash for the next 5 seconds. Your model is transparent and you can move freely.