Group membership diff

Question

I have noticed discrepancies in group memberships: users reporting this see 485 members in Outlook, via groups, and 475 members otherwise. The issue is about users being added via outlook, which are then visible in the outlook group interface, but somehow they do not get added to the underlying EXO workflow and they don't get group emails.

I believe I can confirm the discrepancy via the code below - I can also see 475 members by looking at the permissions of the related SharePoint online site, while the Outlook online interface shows 485 members.

Is there any explanation for this, is it a internal sync issue, is it common/known?
I am wondering how to get the different group views in sync - besides a sync script. I would rather not manage this via support case, if possible, as it would become a very lengthy exercise.

-- members count via Graph

/Users/myself/GIT> $lstmembers = get-mggroupmember -GroupId (Get-MgGroup -Filter "DisplayName eq 'techdevgroup'").id -all
/Users/myself/GIT> $lstmembers.count

475

-- members count via ExchangeOnlineManagement

/Users/myself/GIT> $lstmemberslinks = Get-UnifiedGroupLinks -LinkType members -Identity techdevgroup
/Users/myself/GIT> $lstmemberslinks.count

485

-- members count via az.resources

/Users/myself/GIT> $lstmembersazad = Get-AzADGroupMember -GroupDisplayName techdevgroup
/Users/myself/GIT> $lstmembersazad.count                      

475

-- double check the group id

/Users/myself/GIT> Get-UnifiedGroup -Identity techdevgroup | ft displayname, external*                                    
DisplayName ExternalDirectoryObjectId
----------- -------------------------
techdevgroup ac9c43ce-31ab-4886-9402-a955c6ee2d06

/Users/myself/GIT> Get-MgGroup -GroupId ac9c43ce-31ab-4886-9402-a955c6ee2d06 | ft displayname

DisplayName
-----------
techdevgroup

/Users/myself/GIT> get-azadgroup -DisplayName techdevgroup | ft displayname, id
DisplayName Id
----------- --

techdevgroup ac9c43ce-31ab-4886-9402-a955c6ee2d06

Answer 1

The reason for this is that ExO and Entra use their own directories, and in some cases synchronization issues occur. I have recently reported a similar issue with Microsoft, where Guest users could get added to the members "links" list of a M365 Group, but the change is never synchronized to Entra. Whether you are seeing the same issue in action, or something else, I cannot tell.

The "resolution" here depends on what your goal is. If your scenario is primarily email focused, I'd recommend sticking to the ExO membership list. For any other workloads, use the Entra list.

Answer 2

Hi Michelangelo Bottura,

Thank you for posting your question in the Microsoft Q&A forum. 

Based on the detailed information and PowerShell outputs you’ve shared, I’ve done some research and would like to provide a few insights:

• This appears to be a known issue that has been reported recently, particularly around late August. It is currently under investigation and is likely related to an internal synchronization issue between different Microsoft 365 services (e.g., Exchange Online, Azure AD, Microsoft Graph, and SharePoint Online).
• The discrepancy you're seeing suggests that some users added via Outlook may not be fully synced across all backend services. As a result, these users may appear in the Outlook group interface but are not properly added to the underlying Exchange Online group and therefore do not receive group emails.
• Unfortunately, there is no confirmed fix or official resolution at this time. However, one suggestion that has been shared in community discussions is to try removing and re-adding the affected members. This may help trigger a proper sync and resolve the membership inconsistency.

I understand your preference to avoid opening a support case, as it can be time-consuming. However, if the issue persists or affects critical communications, raising a support ticket may still be the most reliable way to escalate the problem to the product team.

Please feel free to share any updates if you try the workaround, and I’ll be happy to assist further if needed.

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