Extract audio from .mp4 timing issues

I’m running Audacity 2.3.2 on Mojave (10.14.6).

I have a video file that has 500ms of silence before the onset of noise. When I import that audio using Audacity, the audio begins at 544ms. A previous version of Audacity (2.0.6) did not have the same issue—onset of sound appears at 500ms when the audio is imported using that version. Why might the different version of Audacity lead to a timing discrepancy? Might it be something about the FFmpeg build the two versions are using?

Thanks in advance for any guidance!


With that exact same file, or with other files?