Ornn ult bug? Second cast sometimes doesn't hit toward cursor.

I managed to record 2 gif's of it happening to me:

https://gfycat.com/DearAcclaimedBluefish

https://gfycat.com/SilentPastBluegill

When I hit my ult back it sometimes goes in a completely random direction instead of where I'm aiming my cursor. I'm pretty sure this is a bug but if it's not can someone explain why and how this happens? Thanks.