Am I Managing Exceptions Correctly?

I am using BitDefender Total Security on Windows 10 Pro. I go to Protection Features > Antivirus, then click on the Settings tab, and finally on the Manage Exceptions link. I have several external backup drives (USB) on which I keep a variety of folders and files that are backed up from my daily work in Documents, etc. or from downloaded programs, data, etc. To set an exception for all my downloaded material on drive F: I add an exception for F:\Download because all the files in all the subdirectories of F:\Download were scanned when they were originally downloaded. Now, whenever I connect drive F:, BitDefender immediately starts checking the drive. This is fine as not every folder on the drive is excepted. However, a couple of minutes later the scan is still going on and when I check the activity BitDefender is scanning a subdirectory of F:\Download. When I add an exception for a folder (directory) I expect ALL of the subdirectories of that folder to be included in the exception. The manual is silent on this. Is my assumption incorrect? If I have to explicitly add every subdirectory of F:\Download (or other excepted folders) and all the subdirectories of those subdirectories, then the Manage Exceptions feature is useless to me as I would have to manually add several thousand folders. Is there a switch somewhere that says include all subdirectories of excepted folders?

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