First sound file not playing when I export my project

I'm trying to export an animation with sound but no matter what I do the first sound file doesn't play when I export it. I set it directtly at the start and it works when I watch the svg or view the preview but every single time I make it an mp4 the first sound file doesn't play. The other ones play just fine but it's the first one that's the issue. I'm very new to this program so I don't know much. Thanks!