As an update, since we’ve still been seeing issues around date formatting, so we’re pursuing another fix that should help: If you’re using Planner within Teams, we will default to using the same language/local as Teams.
If you’re seeing this issue persist outside of Teams and your language/locale is set properly for your Office account, please let us know in the comments below!
The Planner Team
An error occurred while saving the commentAnonymous commented
Pretty sure I found the manual way of addressing this issue: Settings in your profile icon top right, "General" > "Language" > "App language....". Changed this from USA to NZ and now my planner tasks are in the correct date format.
Hope this helps someone.