Hi Bruce,
Based on your description, can you please confirm the following information?
1. Have you set the correct time zone in your Mac and Outlook for Mac client?
2. Do you have the same issue in Outlook Web App (https://outlook.office365.com/owa/)?
If the issue doesn't exist in Outlook Web App, it is most likely to be related to the Outlook for Mac client itself instead of Office 365.
Given this situation, as our forum focuses on Office 365 cloud service related problems, we suggest you post the issue in our Outlook for Mac client forum for dedicated assistance. Thanks for your understanding.
Regards,
Robert