Mutli-track audio waveform doesn't render in subsequence

When I try to create a sequence with multiple audio tracks, the audio waveform fails to render correctly unless I leave the sequence uncut. 

If I mute everything except for track 1, it remains correct. 

Anybody have any ideas on how to fix it?

Running v14.0 on MacOS 10.14.6 (though it's been doing this for a few versions)