Delta request for Groups sometimes doesn't return createdDateTime and cannot expand 'members'

Library version 2.3.0. When using the standard

GroupsRequestBuilderGetRequestConfiguration

to list groups, the property createdDateTime is returned with a real date of creation for all groups, (system and manually created alike). If I set

$configuration->queryParameters->expand = array('members');

list of members will be always returned. This is expected behavior.

That is not true when using

\Microsoft\Graph\Generated\Groups\Delta\DeltaRequestBuilderGetRequestConfiguration

In that case, createdDateTime will be null in some (but not all) system groups, and list of members will never be expanded.

This kind of subtle incompatibilities makes the Delta API unusable and leads to unnecessary overloading of Microsoft servers, as applications have to poll Microsoft for full list of groups again and again.

Start by comparing GroupsRequestBuilderGetRequestConfiguration with Microsoft\Graph\Generated\Groups\Delta\DeltaRequestBuilderGetRequestConfiguration and the reported group-list responses. Verify why createdDateTime is null for some system groups and why expand=members is not honored; done means Delta results provide the expected dates and expanded members consistently.