Changes do not get applied when trying to modify the source folder Administrators via the QMS API Method

Steps to Reproduce:
1. Load QDS settings by calling getQDSSettings with scope All (FYI it is missing folder administrator info)
2. Load Administrator info by calling getSourceDocumentFolders with scope All
3. Update administrator information on the QDS settings object. Save QDS settings by calling saveQDSSettings.

 https://help.qlik.com/en-US/qlikview-developer/12.1/apis/QMS%20API/html/M_PIX_Services_V12_IQMS_SaveQDSSettings.htm 

Issues: 
1. The QDS Settings returned by calling Client.GetQDSSettings(QDS.ID, QDSSettingsScope.All) returns list of source folder however the list of Administrators is always null/empty. 
2. We were able to get a list of administrators for source folders by calling Client.GetSourceDocumentFolders (QDS.ID, QDSSettingsScope.All). However, we try to override QDSSettings by calling Client.SaveQDSSettins(settings) the changes to source folder administrator do not applied.