The service could be in the setup phase, or it might be used for testing purposes. In such cases, models might not have been created yet.
The account could be undergoing maintenance, or there might be a transition where old models were removed, and new ones haven't been set up yet.
Sometimes, resources are provisioned in anticipation of future use. This could be part of a larger project plan where model creation is scheduled for a later stage.
If the service is being phased out, models might have been deleted, but the resources haven't been fully decommissioned yet.
Check these links :
https://learn.microsoft.com/en-us/azure/analysis-services/analysis-services-logging