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.