Azure Management Groups response body incomplete

Hello,
I've the current hierarchy for management groups:


within parenthesis you can see the level of access I have and in *green* the Managemnet Groups I get as response when consuming the API: https://management.azure.com/providers/Microsoft.Management/managementGroups?api-version=2018-03-01-preview as you can see the list of Management Groups I have access is larger than the ones I get as response, according to the documentation there isn't an option to retrieve all so I would expect that to be the default behavior (same as subscription endpoint does).

Why is this happening? I'm not able to find a rational for it.

Start with the Microsoft.Management management groups endpoint and its 2018-03-01-preview documentation. Compare its response behavior with the subscription endpoint and the management-group hierarchy shown in the issue, including the reported access levels. Done means explaining the discrepancy or identifying the specification or documentation change needed.

Written by the indexing model from the issue text.