Waveform Conforming is truncated and misaligned

This is a weird, intermittent problem that I haven't seen anyone describe yet. I updated to the latest version of PPro today (Feb-21-2020) and I'm having the exact same issue.

I recorded about a dozen 5-minute clips, making separate videos in separate projects for each one. Most of them are working fine, but on three of them when I import the clip, the waveform finishes conforming but it starts about a minute or so into the clip. The audio ends where I stopped recording, but the audio clip has blank space at the end equivalent to the missing audio from the beginning. 

The really bizarre thing is, when  I play the raw video clip in the Movies & TV app in Windows, it plays fine. The audio is exactly where it's supposed to be. But when I import it into the file, it cuts off a minute of audio and adds a minute of dead space at the end. Three files have randomly done this and I don't see anything special or different about them.

Also, on some of the other clips, the waveform doesn't conform at all unless I import it, save the project, close it, and then re-open it. Then it conforms and everything is fine. But again, it seems completely random. These clips were all shot on the same camera, the same day. I can't understand why they'd act any differently from each other. 

I have no idea what's going on. I even tried deleting the file from my hard drive, and copying it back over from the memory card but the exact same thing happened, and only on certain files. And the raw files play fine. Something is happening during the import process, and it's not conforming correctly. But I don't know what to change. I'll attach screenshots of the issue and my audio  and media cache settings.

Help!!