[SPECTATOR MODE] After rewinding a finished game, only champion voices are audible

When spectating, if you rewind a finished game the only audio left are champion voices.

1. Spectate a game
2. After it ends (not sure how long), rewind Was spectating a friend when I happened to cause it. After realizing what had happened, I remembered I've seen this happen in the LCS several times. Spectated a separate game later and recorded it happening again. I play with Music/Ambience muted, but set volume levels to default for the recorded example. The bug happening in LCS recently. Skip to 1h22m if it doesn't automatically. (cst vs dig spoilers)