The transferred data file has fewer records than expected when it is opened.
Data can be lost during an FTP file transfer.
A good way to avoid getting a partial file during a transfer (either by FTP or email) is to zip the file before the transfer, using the zip command in unix. This will make the file smaller, and you will get an error right away when you open it, if any data was lost during its creation. Unzipped plaintext files that get corrupted do not give errors when opened and can look deceptively fine when opened, unless you look at them closely.