Hi Noé, this is indeed expected. The reason is that when stopping the container, all the crossfades scheduled in the sound engine are cancelled. This means the sound will therefore only play one last time and will finish before the end of the fade out.
There is a pretty simple workaround to that: use the " Set Voice Volume " Action instead of the fade out option. With that Action, you can set a time and a target volume, its easily replacing a fade out. Don't forget to put the voice volume back to a " normal " value after your event/fade out is done.
Hope this helps ! ( Passe le bonjour à l'ENJMIN de part ;) )