Using EWS to update calendar name in Outlook.com doesn't register online

Question

I'm using Exchange Web Services to update a calendar name by setting the DisplayName property and then calling .Update().

It works in the sense that the call completes, and retrieving the calendar through EWS later, the DisplayName has changed, but Outlook.com doesn't register it and just shows the old name.

So basically it works but Outlook.com ignores it. I'm following the code sample here: https://learn.microsoft.com/en-us/previous-versions/office/developer/exchange-server-2010/dd633615(v%3dexchg.80)

Folder folder = Folder.Bind(service, folderId);
folder.DisplayName = "Updated folder name";
folder.Update();