The Recycle Bin appears to be functioning correctly, in that the context menu option to 'Empty Recycle Bin' greys out, the icon changes, and even the $RECYCLE.BIN folder (and subfolder 'Recycle Bin') show empty (hidden and operating system files not hidden) with total size around 20K.
However, when running a full Windows Defender scan (with an "empty" Recycle Bin), a large list of files are lsited as being scanned within the Recycle Bin, within a sub-folder (not otherwise shown) corresponding to the HKEY_USERS key 'S-1-5-21-xxxxxxxxxx-xxxxxxxxxx-xxxxxxxxxx-xxxx' (actual key replaced by x's).
When used Explorer to go directly to folder 'C:\$Recycle.Bin\S-1-5-21-xxxxxxxxxx-xxxxxxxxxx-xxxxxxxxxx-xxxx' I am taken to 'C:\$Recycle.Bin\recycle Bin'. which is of course empty.
If I manually delete the Recycle Bin a number of folders and files are listed for confirmation to be deleted, which also are not listed within Explorer (or on Recycle Bin properties).
The Recycle Bin is automatically recreated, and the hidden files seem to disappear, but the problem again manifests itself over time.
Why are these file not being deleted by emptying the Recycle Bin, why can I not see them, and how can I delete them routinely?