Excel inserts an EOL into the data when importing from a CSV file ...

If I import a CSV file with only this string - "TLEDBDB,Dummy" in it (no quotes in the file), an EOL character is inserted in Excel right after "TLEDBD". Also, if I open Outlook & paste the same string in the CC line, it also inserts an EOL in the same place. That string turns out to be part of a serial number I need to import from a CSV file. What's going on?