Recorded Highlights do NOT record audio along with video

Just played a game on ARURF. For bragging rights, got myself my first 2019's Penta (#URFOP)... [garen-swing] ... but that's besides the point... As I downloaded that game's replay to record the highlight, I noticed that the recorded video didn't have audio. But weirdly enough I managed to record the same highlight but with a wider time-window and noticed that on a certain moment, something drew the sound to be muted. Not really sure what exactly. Perhaps an audio trigger/multiple simultaneous sounds at the same time in the game itself. Or just another Spectator bug...