I'm still having the issue. I can see the waveforms in the sequence and it did start playing when I first started up the program, but it stops working after a while.
Dave Helmly from Adobe posted this in one of the Premiere Facebook groups a couple of days ago. This might help solve your audio issue.
In case people are still experiencing the v12.1.1 Audio Bug in a current project with our most recent update V12.1.2, here's an official post to help clarify what's happening and how to fix the v12.1.1 project.
V12.1.1 UI Audio Bug
The issue could occur when an audio track was muted in a sequence and then the v12.1.1 project was saved and closed. When you reopened the project, the UI for the sequence no longer showed the audio track as being muted as the UI reset the toggle to show it as on. When a user would play back the sequence , not all of the audio tracks would appear to play causing them to possibly think it was a caching issue or codec related issue. Premiere was actually playing the sequence back correctly as those tracks were muted from the previous save state but the UI bug caused the issue where there was no indication that the track was muted.
Solution: (the Fix)
Once a v12.1.1 project shows this UI behavior it needs to be corrected and resaved. **Note** v12.1.2 will not correct this issue simply by opening the project in V12.1.2 .
You need to follow these steps to repair the project.
1. Toggle the Solo button on/off and the Audio track will correct the playback state. To keep it simple, Solo/Unsolo each audio track.
2. Playback the Sequence to insure that all audio tracks can be heard and monitored.
3. Save the Project
4. Quit Premiere Pro
5. Relaunch and issue should now be fixed.
As stated, the fix for this issue is included in the recent update, v12.1.2. This update keeps the UI bug from occurring so the user should not run into the issue again.
Hope this helps - Dave
Looks like Adobe has put out a bug fix and if you install that it works now!