$expand with $count fails when having a join table

[wog48]

When trying to get the number of expand entities e.g., .../entitySet?$expand=navigation($count=true), the service response with a http 500. The error message states:

ON condition right attribute is null / not found.

[dbhandari555]

Can you please provide an example for the above mentioned scenario using the entities defined in sap-jpa project? I can't reproduce the issue. For example, I tried Organizations?$expand=Roles($count=true) and it succeeds without error.