Because the concept of device doesn’t exist for Dynamics CRM Online as far as I’m aware of, so a shared service account will take the role as a ‘device’ in this case and get assigned the device license.

And users will take turn access the Applications corresponding to the device licenses assigned to the service accounts. In the Licensing Guide, it does mention that “Device licenses may use shared logins (such as “Warehouse Computer” and a shared password) or individual logins (each user’s personal credentials), depending on the application and license.”

Currently, this is the default nature of the Device license for Dynamics CRM Online Platform.

However, this doesn't meet the requirement of some users since some companies don't allow to use Common Id (shared Id) under any circumstance. What is expected here is that each users will sign in with their own account and password instead of shared account and shared password. So, this design is flaw in this this type of scenario.

And since we don’t have any suggestion at this moment to bypass this mechanism for the device license, we hope Microsoft can adjust this design to support scenario like this.