The problems are exactly the same as mine!
There are audio waveform in audio tracks but I can’t hear the sound.
I can hear the front part well, but I can’t hear it from somewhere.
I also run 5 video tracks and 3 sound tracks. Since a few days ago I can’t hear the back of the third audio track. This is progressing more and more. For example If you didn’t hear the 10 cuts from the back yesterday, you can’t hear 20 cuts today. I keep bringing the original source and changing it, but it’s too cumbersome and difficult to get many cuts. I don’t think it’s convenient to edit multi-cam in the premiere pro.