Auto attacking while in Animation / Stasis for Guardian Angel

While playing, encountered a bug where I (Talon) was killed by a Jayce while he was in the stasis for GA, From the video you can see that his HP Bar depletes, and is untargetable but is still about to get off one last auto attack, while in stasis. I haven't ever seen this bug recreated, but was able to tell right away when it happened, that something wasn't right.

Happens around 15 second in the video.