Composite Model error: "Cannot load model" - connecting to dataset fed by Databricks Connector

Hi all, 

as I'm new here I hope anybody can help me with an issue regarding the composite model feature. 

This is the situation: 

• First I made up a "one table" model by using the databricks connector to connect a simple table in import mode 
• Power BI Desktop Version is 2.88.802.0
• I uploaded the Power Bi Desktop file with this model to a workspace with a Power BI embedded instance. 
• refreshing and displaying data works fine
• Then I opened a new PBI - Desktop file and connected to the dataset of the mentioned workspace. Works also fine.
• Now I clicked on "Make changes to this model" and received the following error
  • "Cannot load model" - "We couldn't connect to your direct query data source..."
  • I can see the model
  • But I cannot use it, e.g. one cannot put fields into a visual

As I tried the same thing with connecting to an AAS cube via direct link, everthing works fine. I added the same table from databricks, connected it to the AAS model and deployed a new dataset based on both data sources.

Connecting to the AAS/Databricks dataset the error occurs again.

For which reasons I cannot use deployed datasets as a source for composite model? 

Best regards

Thias