Microsoft Team Members are not in the associated SharePoint site Members group

Question

Context

I created a Microsoft Team which created an associated SharePoint site.

I created a SharePoint List on the site and have granted the default Members group a custom permission level on it.

The custom permission level is nothing fancy, it is just designed to let users add items, but not delete or edit them.

I believe, by default, Microsoft Team members are added to both the Visitors and Members groups.

Desired Behaviour

Users who are members of the Microsoft Team are also in the Members SharePoint group and therefore can be granted custom permissions on lists etc.

Actual Behaviour

Users only have Read access on the list, which is the permission level that users in the Visitors group have.

Microsoft Team members do not seem to be in the Members group and therefore do not have the custom permission level applied.

I think I may have caused this behaviour by clicking on the Settings cog in the top right of the site and changing the Members group permissions in the Site members section:

If that is the case, how do I get the Microsoft Team members back in the Members group?

PS

I am confused because the site still lists the Microsoft Teams Member count:

Related Screenshots

....sharepoint.com/sites/group-name/_layouts/15/groups.aspx page:

....sharepoint.com/sites/group-name/_layouts/15/user.aspx page:

Clicking on the default Owners/Members/Visitors links does not list any users, however when i click on the Members group and then New and Shared With - the Owner and Member groups seem to be listed, eg:

Checking permissions for a Microsoft team member:

Related Reading:

https://sharegate.com/blog/how-broken-are-office-365-sharepoint-permissions

Answer 1

By default, the M365 Group Members are in the SharePoint Online 'Members' SharePoint group. Looks like someone altered the permission level of the M365 Group from Edit to Read (or used the classic SharePoint UI).

You just need to change the Members group permission from Read to Edit.

Answer 2

The site members section always displays the members in the SharePoint group "Site Name members".

By default when the team site created automatically by M365, the M365 group members shall be added to the SP group. It could be later changes which removes the members from the SharePoint group, which makes you cannot find them in the site permissions> members section.

Just add the members back to the site members group, you can find them in the site permission section. It is not a issue with permission level, but the group.