Getting Kills After the Nexus Dies

When i was playing a game of urf, the entire enemy team was gathered infront of the fountain as the minions were destroying the nexus. I was playing morgana, and i was shooting as many of my spells out as i could, and i cast Tormented Soil under the enemy gragas, who was in stasis from zhonyas hourglass at the time. After the nexus was destroyed by the minions, gragas's stasis effect ended, and tormented soil was still under him so the remains of his healthbar melted and i got a kill during the defeat screen. The steps that I believe would lead to this bug being reproduced are

1. Let the game progress to the point that it is possible to end the game quickly
2. Have a character with low health activate zhonyas hourglass (or possibly any form of stasis, but zhonyas seems easiest)
3. Place an aoe dot under the champion in stasis that will last long enough to kill the champion after the stasis ends
4. End the game before the stasis ends I believe i have only encountered this bug once, but i have not tried to reproduce it yet as it just happened.

Edit: I have encountered this bug twice now, this time the enemy lissandra zhonyased and i dealt damage as ahri with my Fox-Fire, however i did not kill her.