Hey @Clubman, thank you for posting in our Community!
And thanks for sharing the details. The issue could be related to time zone settings, how HubSpot handles all-day events, or a syncing problem with the Outlook plugin.
Double-check that both Outlook and HubSpot have the same time zone settings, including daylight saving time.
If possible, try setting the start and end times for all-day events as 00:00-23:59 instead of using the “All Day” checkbox. If the issue persists, consider reinstalling or clearing the cache for the Outlook plugin.
Let us know how this works.
Kindly,
Pam