I am having this issue too, but for live chess. Every time a piece moves it makes two sounds. I refreshed the page and it continued to happen. It’s sad that it has not been fixed yet, and your post is from 2021, so it must have been a bug for multiple years.
Double sounds when moving pieces in analysis?
I'm having this problem today and it's 4 months after the last report of this. Several months ago, I had multiple clicks beyond 2 only when I moved a piece. That happened today and after I closed the tab and opened Chess.com on a new tab, the multiple clicks turned to this 2 clicks per my move and my opponents move. OMG! I've tried clearing cache and changing browsers. Nothing helps. When this happened several months ago, I think I had 2 tabs open a the same time....not sure. Somehow I fixed it at the moment. This time I can't.
I found that sometimes when this double sound occurs, I have another tab in another browser open in chess.com. Once I close the 2nd tab, this double sound goes away. But I'm not sure if there's a 2nd tab open all the time when this has happened to me.
Well, this evening triple sound cicks occurred with no other tabs open in any of my browsers. I eventually quite out of Chrome completely (the browser I was accessing Chess.com. And when I restarted Chrome, the extra sounds stopped. But before I exited Chrome entirely, I tried clearing the cache but that didn't work. But at least this time anyway, closing Chrome and restarting it fixed it this time.
When doing puzzles or going over a game if you go back and forth between the moves sometimes it makes twice the amount of sounds and it's quite obnoxious. It started a day or two ago. When doing puzzles if you go through the moves it actually also makes 2 moves per keyboard arrow button. Really annoying.
Hope this can get fixed soon.