The latest version of Impress (18.104.22.168) appears to lose transition sound files when the Impress file is saved.
Edit: It also loses ‘system’ sounds (eg ‘Applause’), and forgets the ‘Stop Previous Sound’ command.
Edit: 5.3.7 behaves the same way.
A presentation has slide transitions with sounds. The sound files (mp3) are in the same directory as the presentation. The presentation stored under previous versions works as expected, even when re-opened under 5.4.4. When the presentation is saved and re-opened under 5.4.4 … no sound. If the sound files are re-linked, they work while Impress remains open. When the file is saved and re-opened, the transition sound is specified, but … no sound.
This looks like a bug, unless I am missing something.
Ubuntu 16.04 LO 22.214.171.124
Now fixed in v6.1.2, which seems to be an all-round good version. Well done developers!