Exchange Online Username/Object ID

Hi,

Problem exists since 4-6 Weeks.

We want to give FullAceess to Shared Mailbox in ARM for new created with Arm-Template.

In Arm-Search we see  the Useraccount from lokal AD and Azure correct:

When select the Exchange Account, we see only the Object ID from Azure in User List:

The Problem is only at New Users!

Is something new in Azure or where is the Problem :-)

Someone an Idea?

Thanks for Feedback.

Regards