Hello Joey,
Thank you for your reply. We are using Outlook for Mac 16.36 on Mojave and Catalina. The issue is specific with Delegates who want to convert one Occurrence (into a Teams Meeting) within a Series.
The Delegate will proceed with the following steps:
1. Double-click to open the Occurrence.
2. Click on the Teams Meeting button in the ribbon
3. The Delegate gets an error "Online Meeting - This is one appointment in a series. To make it an online meeting, open the series and try again."
NOTES:
1. if the user converts the series to Teams meeting, she is concerned that information (in future Occurrences) will be obstructed or altered by the Join Meeting button that gets automatically added.
2. In Windows, if the Admin double-clicks on an Occurrence, he or she would be prompted immediately to choose wether to edit the entire Series or Occurrence. The Admin can simply choose to edit the Occurrence and convert it to Teams with the button.
2. I found the Teams meeting button (in Outlook for Mac) to be unreliable or inconsistent when I converted meetings or Series to Teams meetings within the Outlook for Mac application. After converting to Teams, sometimes the Join button would be visible,
but sometimes the join button would not be available. If the Join button was not available, I could not try to re-convert to Teams meeting because the button in Outlook for Mac would no longer be visible.