ipad – Audio silence at the end of m4as in SOME, but not ALL audio players in iOS

I have a collection of audio files in the internal memory of my iPad. The files are primarily M4A. When I play the files in the standard player of Apple Files (or FileBrowser), there is a lot of silence in the end. Usually at least 10 minutes. However, if you open the files in VLC Media Player, the silence is not there – the audio will stop working correctly. Why is this?