I posted this bug to Riot player support, but they told me to post it here instead.
Akali was counted into the battle royale despite being in "Zhonyas" in base, I haven't seen this happen with any other champion yet. The circle closed in on me when I was the last person standing, causing enemies to win the event.
Match Details: https://matchhistory.euw.leagueoflegends.com/en/#match-details/EUW1/3752324757/208666135?tab=overview
Type of Bug: In-game