The memo reads:

" If a customer hears a popping sound when playback is stopped on their MacBook Pro (16-inch, 2019) When using Final Cut Pro X, Logic Pro X, QuickTime Player, Music, Movies, or other applications to play audio, users may hear a pop come from the speakers after playback has ended. Apple is investigating the issue. A fix is planned in future software updates. Do not set up service, or replace the user's computer, as this is a software-related issue."

In addition to those specific apps mentioned in the note, users have been able to replicate the same issue with YouTube, SoundCloud, Safari and Chrome. As you can see, Apple didn't expound on what that software issue is, and it's unfortunately unclear when the fix will become available. You'll just have to wait for it to come out, though you can try some of the temporary fixes other users have been suggesting if the popping is bothering you too much.