LSL6: Saves may not restore with working music fade-out

[RayKoopa]

• ScummVM 2.6.0git6340-g974c51b4cd1 (Jun 5 2022 09:42:22)
• Game language: English
• Game version: Hi-Res 1.000.000
• Windows 11 21H2 10.0.22000.675

Steps to reproduce (not 100% sure yet):

• Leave a room which causes a 5 second volume fade-out of the previous room's background music before starting the new room's music (for example, when entering the hotel interior from the pool).
• Save the game while the fade is in progress.
• Restore this game.
• Notice that there's a chance of the previous room's music now being stuck at the volume at the time of saving.

In DOSBox, the behavior is different: The fade-out of the previous room's music "restarts" at full volume and full 5 second duration, and then properly starts the current room's music.

I cannot reproduce this 100% yet, and attached a save game where this did happen, but I remember this happening quite often when I tested the previous music channel bug on fresh games. I'll update the ticket once I found a safe way to reproduce it or attach simpler saves to it.