Both failed Apple’s test in the store. There was a repair program for audio issues - but my pair was made supposedly 4 months after it was fixed, so I had to get a new set.
I also had a MacBook 2017 which clearly, obviously, developed the stage light backlight issue. Only to find out the repair program only covered 2016 models.
Thus, if I had a nickel for every time Apple had a repair program for the exact issue I was having, but only up to the model just before mine, I’d have two nickels. Which isn’t a lot, but it’s weird that it happened twice, right?