Leading or trailing spaces in fields that appear in Browse Elements (probably Project too) will result in "duplicate key" error on project import. 

  • [00.01] is ok 
  • [00.01 ] results in error 
  • Error example (note that after "72" in the error message there is a space):

Note: As of version 1.8, Cortex will automatically strip trailing spaces but leave leading spaces alone in the event the data requires it.