I'm trying to get a list of all the ad extensions in an account at account level, campaign level and ad group level.
I've used the CustomerExtensionSettingService and the CampaignExtensionSettingService with a selector applied containing the fields: 'ExtensionType' and 'Extensions'.
This all seems to work fine, and I can see a list of entries.
When I try and use the AdGroupExtensionSettingService to retrieve the extensions however, it does not work. Weirdly, I can see the entries exist as the 'totalNumEntries' property on the page is populated. However the 'entries' property is null.

(see screenshot above of my AdGroupExtensionSettingPage object).
Any help would be most appreciated.
Joe