Explanation for cassio ultimate bug?

Iv'e been seeing youtube videos and reddit posts of people being stunned by cassio's ultimate despite clearly facing the other direction. I personally haven't heard an explanation. It happened to me and I did some digging and may have found the reason, it's much simpler than I thought, the ping! If this isn't a correct explanation and it has nothing to do with ping than it is a serious bug. Let me know if you agree with this or not.