group REST call doesn't show all groups

[ericleigh007]

I'm doing the following REST call as a GET.   

            var requestURL = $"https://api.powerbi.com/v1.0/myorg/groups";

            HttpClient client = new HttpClient();
            client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", _authHeader);

            HttpResponseMessage result = await client.GetAsync(requestURL);

This succeeds, but only 2 groups are being returned.  There are at least 3 groups to be returned.

The account i'm using is a service account that is a member in all the groups I'm attempting to list.  The app has Groups.Read.All permission.

I messed around with the group members, and found out that even groups I'm not a member of can be listed, but some groups I am a member of are not.

I'm stuck.  

I'd like this app to be able to see all our groups, so that I can get the groups by name, and look up the GUIDs which will enable me to list names in a control file, and not GUIDs.

-thanks

-e