Embedded audio, only 1 mp3 works on another computer

Greetings.
My friend has sent me a .ODP (created with LibreOffice Impress 7.5.4.2, Windows 10, x86_64) with embedded .MP3 files. She sends it to me (7.6.4.1, Manjaro Linux) and only one of the several audio files plays. She sends it to herself and the same behaviour - and all the non-playing files have a film tape icon.

What we have tried:

  • Tried: Copying working media object to another slide. Result: still works
  • Tried: Inserting same MP3 into another slide from file explorer. Result: audio does not work on new slide, even with the same file used.

It works flawlessly in the original .ODP file. We have tried using/not using animations/misc/start media and nothing changes.

Thank you!