Hello,
it is definitely not normal behavior that Audio files are duplicated in the trash folder. Files only appear in the trash after deleting them. I am unable to reproduce the issue at the moment, so I would be interested in further details about your issues. For instance: What operations cause the duplication (Undo?)? Could you provide a series of steps that I could follow to reproduce your issues? How many files are in your project? You can also send me a project where the issues occur so that I can reproduce it.
Thanks for your help and kind regards,
Frieder