Nidalee spears seemingly invisible

So i have been noticing a bug with Nidalee spears in my recent games where they seem to be invisible with only some small effects on them. At first i kinda just forgot about it because it never really bothered me. But this morning against Headhunter Nidalee, i would just be casual strolling through the rift when i would just randomly die only to figure out that it was actually her spear the did me in. I don't believe i'm the only one who has noticed this so if anyone could explain to me why this happens it would be much appreciated.