Hey Steven, hope you figured out a solution. Just had the same thing pop up and could only find your post here as the only other person who this has happened to. I ended up just figuring out where the waveform desync occurs, exporting the audio from the original clip (thankfully just had to do the one), and then replacing the original audio with the newly exported audio. The newly exported WAV file has the correct waveform to it all the way through. It’s not pretty by any means, but it’s gonna keep me from slamming my head against the wall.
A few extra notes, I’m using the latest version of Premiere (12.0.1) on a PC, working with GH5s 10bit 4:2:2 L-GOP footage.