Lissandra Ultimate Bug [GAMEPLAY]

In my last match, I was experiencing a rather frustrating bug with Lissandra's ultimate. It's workings are as follows: when her ultimate is successfully cast onto an enemy champion, and that enemy champion moves out of the cast range or becomes temporarily untargetable during the extremely brief window before the effect of the ultimate takes place, the ultimate instead hits another random enemy champion within the cast range. If there is no other enemy for it to hit after the originally targeted enemy moves out of range or becomes untargetable, the ultimate will self-cast. To recreate:

1. Cast Lissandra's ultimate onto an enemy champion.
2. Have that enemy champion quickly flash/dash/jump out of the original cast range before the ability actually strikes.
3. Be very confused as to why the ability hits someone other than the original target.
4. Weep in a corner...

Hopefully someone at Riot sees this and tests it out so it can be fixed. It happened to me a total of 3 times in my last match. I know the last 2 steps that I provided can be considered comical, but I am being serious about the bug existing and causing problems. Any feedback will be greatly appreciated. Thank you for your time.