Arcade Hecarim Makes invisible characters visible

I noticed this in a game i played yesterday, and i dont know if this works with any other skins that work the same way. When i use my W, Spirit of Dread, it creates a distortion effect on enemy champions as arcade hecarim, gets enemy blurry, and slightly brighter. If you use this while an enemy invisible champion is present (in my case, a shaco), you can see the particles created, but not the enemy itself. Basically it works like a slightly less visible red trinket

I main hecarim and had arcade hecarim since it was released, but i havent noticed it before, i think its new.