I assume you’re on Windows. Can you try closing Dorico, opening Explorer and typing in the path bar:
%TEMP%\Dorico 3
If there’s a directory in there called Soundtracks then delete it. Start Dorico and load the project file again.
If this doesn’t fix it then please go to the Help menu and choose Create Diagnostic Report, then attach the DoricoDiagnostics.zip file that’s on your desktop.