I have migrated all of our Exchange 2010 mailboxes to Exchange 2013. The old Exchange 2010 servers still exist as they have yet to be decommissioned but they have no mailboxes on them now.
Ever since migrating the user mailboxes to the Exchange 2013 servers, users now get the following every time they try and add members to a distribution group:
Changes to the public group membership cannot be saved. You do not have sufficient permission to perform this operation on this object
I have looked at the Exchange 2013 EAC and can see that the "Default Role Assignment Policy" is assigned to the user mailboxes and the "MyDistributionGroups" role is enabled. The Outlook clients are a mixture of Outlook 2013 and Outlook 2016 and I get the same problem on both.