Audio of project (MP4) changes as soon as its published

Hi,

As soon as I publish a MP4-project with videos and audio, the audio-quality becomes much worse (about 14 .cpvc files). When I play the project before I publish it, it sounds perfectly fine. Afterwards publishing it has weird noises and weird stops (only the audio). Does somebody have the same issue and knows how to stop it?

Thank you.

Adrian