nexus blitz: i get fake kils in batle royale

the game (nexus blitz) went normal until the event batle royale started. i was fighting a bit with talon as champ and i did dmg at 4 persons. one of the 4 died in the circle storm of batle royale and the moment he died, i got a quadrakill out of nothing, but 3 of them where stile alive. i didnt got kill gold or kills but my match history told me i had a quadrakill. the weirdest thing is that the ones who i killed for the "quadrakill" where two of them and two of my teammates so i killed my own teammates? all the kils where killed by the storm, so it was like the storm was mine ability. pls riot explain me why this happened link tho replay : file:///C:/Users/elias/Documents/League%20of%20Legends/Highlights/8-16_EUW1-3739218493_01.webm