Don't know why, but it's definitely "Undien".
And correcting it will make the file invalid when trying to import it. IOW... it has to be misspelled or Sentinel sees it as invalid.
Question is... do they "fix" it in the next version of Sentinel and break all the old exported configs floating around (including those you may have backed up)?
It isn't mission critical, it just looks bad when inspecting the xml. Fixing it would probably cause more confusion than just leaving it alone and living with the typo.