There should be no difference because the video track hasn’t been touched. Some software will display the length of the longest track rather than the length of the main video track. It’s likely that the the audio track was originally longer than the video track and because of the offset it’s now shorter.
You can use tools like ffmpeg and mediainfo to count the actual frames in each to verify.
What’s the deal with Alpine not using GNU? Is it a technical or ideological thing? Or is it another “because we can” type distro?