MP4 audio muted on import

When trying to import new video files to Premiere, their audio is muted. I can watch them in Media Player just fine, video and audio perfectly synced. But once I try importing any of them to Premiere, the file imports with an audio track, but the track has no audio on it. The video plays out perfectly, but no sound at all.

I've tried converting the files to different formats like MOV and AVI, tried using Media Encoder to change to other suitable files, nothing. When importing other videos, there are no problems, everything works as normal. It's only these files. The files are perfectly normal MP4's and have all the same details as files that do work. Size is not an issue, as I've imported videos far larger than this, also with no issue.

The only difference is that these are recordings from a VR headset. Which also shouldn't be a problem, because I have used VR recordings before with no issue, and can still import other VR recordings with their audio intact. I have been troubleshooting for the last 4 hours with no results and am completely stumped. And yes, I did clear the media cache multiple times.