Hyphenation Differences between PoliteMail Online and Outlook
If you composed an auto-hyphenated message in PoliteMail Online, on rare occasions you may notice the hyphenation is different when the message is viewed in Outlook for the Windows Desktop or Outlook for Microsoft 365. This is because PoliteMail Online uses the language rules of your browser, but Outlook has its own language rules.
The only workaround would be to manually insert hyphens (-) where you want them. You can also insert a non-breaking hyphen if you have a hyphenated word that you do not want to be split into two lines, usually by selecting the word and pressing Ctrl+Shift+hyphen.
You can find more information about the auto-hyphenation feature here.