V2.26 and V2.26.1 of the Microsoft Graph PowerShell SDK were low-quality, buggy disasters. Microsoft aims to fix the problem in the next version to make it possible for the SDK to work with Azure Automation runbooks again and address many of the obvious problems that should never have appeared outside Microsoft. It will take time for customer confidence to be restored.
Some problems emerged in V2.17 and V2.18 of the Microsoft Graph PowerShell SDK. In one case, Microsoft changed cmdlet names. In another, it’s an identity issue caused by incompatible assemblies. In both cases, questions have to be asked about the level of testing done by Microsoft before they release a new module. Bugs do happen, but testing should catch the obvious problems.
After a while, you discover the holes in any technology. In the case of the Microsoft Graph PowerShell SDK, some inconsistencies await unwary developers. The SDK doesn’t like $Null, doesn’t support pipelining, insists on specific property casing at times, sometimes accepts user principal names and sometimes doesn’t, and sticks valuable data in hash tables hiding in a property you might know nothing about. Good as it is to have the SDK cmdlets, they need to be treated with care as you transition from the old Azure AD and MSOL modules.