Automator: Filter Finder Items selecting wrong files
Finder uses the kMagicBusyCreationDate for files currently being downloaded, which is 08:34:56 on 1946-02-14 (+0000).


  Use this date as a file's or folder's creation date to indicate that it is temporarily busy (while it is being downloaded or installed, for example).


What is the significance of 1946-02-14 08:34:56?

As this is well outside your date range, the file is removed immediately. Therefore you can’t use any date based checks whilst files are being downloaded.