Jhin ult sometimes doesn't hit properly!

Recently I've played Jhin in blind pick normals. I'm currently obsessed with this fabulous champion but I've come across the bug that occurs with his ult. In some rare cases I've encountered a bug in which the projectile, when it does make contact, acts as if it didn't hit them at all. I currently do not have any footage at the moment but i currently am in the process when i can get the moment. please, if u can, find out how to do this and fix it because it is such a bummer losing a kill because of a silly bug.

Sincerely, silver scrub FlyiNngRhinO MAn.