https://twitter.com/MiLB/status/1164166685198311425?s=20
I'm assuming they had the outfield shifted over to the left field line?
If we're going RBI here, my guess was that the right fielder was up against the wall when he threw it, so the throw bounced into the stands.
Apparently, the throw was so bad it went past the outfielder, who had to chase it down after it bounced off the wall. By the time he even got to it the runner was at 3rd.