No direct experience with this issue, but found this forum thread kicking around some solutions. Seems to be related to the VLC audio settings. Though the thread starts in 2012, there's a 2018 post at the end that continues to contribute to the troubleshooting ideas. Maybe something in there will help.
I was going to mention the "remove silent channels" option and the two or three around it. I had them selected a couple days ago and they deleted all my audio on import (camera audio anyway). Upon re-importing without them selected the audio was there.
Sorry I don't have a better answer. Do you have any other audio options checked?