R U sure you did a Ctrl+C then a Ctrl+V (i.e. a copy), and not a Ctrl+X then a Ctrl+V (i.e. a move) - done it myself often enough.
If you normally access E-Books\calibre_portable.exe via a shortcut then the DLT service would have detected the move and adjusted the shortcut to reference the instance in your downloads folder (that's its job - shortcut fixing).
BR
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