you will face this issue if you double click and open the business file from your Windows Explorer. because Manager imports it as a new business. so after importing it as a new business, the newer entries are stored as a separate business file. this is the reason you are seeing more than one business files in your Application Data folder.
this behavior is already listed as a bug.
after moving your backup file to your Application Data folder, always open Manager and select your business listed in Manager rather than directly opening from your Windows Explorer.