Old files in Audit Folder

Hi Team  ,

We are observing old files in the audit folder in  in our multimode  clustered SAP BO 4.0 installation. Files automatically appeared of their own with old date time stamp. Few days ago we have set the retention period of Audit DB  to delete the old Audit DB. Could it be related to this.

What needs to be checked.

Regards ,

Abhinav