I’m the one who reported it over at the MakeMKV forum.
I had a feeling that this is an old issue since I’d seen it before on a few Atmos titles but not to the degree of Incredibles 2. With other titles, you’d get a momentary drop out and then everything would be fine. Not only did it happen a lot in Incredibles 2 but there were spots where the sound wouldn’t come back at all.
I use an Oppo 203 exclusively for playing my Atmos titles. Oppo tech support says that the same sound code is used for all inputs regardless of where it came from. Everything is ripped with MakeMKV, currently on version 1.14.1. For Incredibles 2, there are a number of places where drop out can (and usually do occur).
Chapter 1: 1:40 (Car nearly dropped on Tony Rydinger)
Chapter 2: 4:59 (Underminer leaves the fight with Mr. Incredible, “Bye-Bye!!!”)
Chapter 6: 16:40 (Winston Deaver meets the Supers, “I love Supers!”)
Chapter 14: 46:35 (Elasticgirl boards the helicopter, “Stay in your seat ma’am!”
Chapter 14: 47:00 (Elasticgirl kicks Ambassador’s security out of the helicopter and executes a loop de loop)
There are other places but Chapter 14 is easily the most reproducible of the bunch. The helicopter doing the loop de loop in Chapter 14 is so bad that the audio drops out for a few seconds and sometimes doesn’t come back at all. My Marantz 7703 processor’s front panel lights just drop entirely when the audio problems occur here where in other places on the movie, they may blink momentarily.
I also have the movie completely backed up via MakeMKV to a file structure that I can play with my Oppo 203 on a Windows server via SMB. When I do it that way, it plays perfectly. If I use an MKV file, then I have the problems.