Audio out of sync in long sequence in Premiere Pro CC

[Swamplander1]

I have a sequence and about 47 minutes into it, I notice the waveform in the audio track is out of sequence with the playback. Everything sounds fine, but the waveform doesn't match what I hear.

For example, in the picture below, when the play head moves through the #1 section, I can hear the audio... it's not silent.

This has happened before, but I don't recall if / how I fixed it. I've restarted Premiere, even rebooted... but no change. Running latest Premiere (12.1.1 Build 10) on latest MacOS (10.13.4).