Do not create duplicate calendar invites when forwarding an invite to an Office 365 Group
TL;DR: Forwarding calendar invites to an O365 group creates a calendar invite in the group and re-sends the invite to all original recipients on the invite (whether they are in the O365 group or not). I would expect this to work like a traditional distribution group where new members are added to existing invite.
So, imagine this... There are two groups A and B. Group A is a collection of individuals already on the invite. Some members of Group A may be in Group B, but there are those in Group A who are NOT in Group B. Group B is the O365 group that I want to get the invite. However, since I do not "own" the invite, I Forward the invite to Group B. This forwarding action then adds the invite to the Group B O365 Calendar. Because of the action of adding to the O365 calendar, it re-sends the invite to Group A as well as Group B. I have attached a screenshot of what this looks like to a user.
This has nothing to do with the calendar on the web. It's not an overlay, it is a duplicate. When I veiw the O365 Calendar and my calendar on OWA, I see 4 of the SAME invite as it is duplicated in both my personal calendar and the O365 calendar (I'd expect to see 2-one in each calendar).
The issue isn't that the Group B members are getting the invite, the issue is that the invite is being duplicated and re-sent to EVERYONE on the invite.