It seems that the "Entities Return Mode"-setting "Incoming/New" under some circumstances prohibits reading EDC-managed entities. In these circumstances the setting "All" performes the desired read-actions. I'm not talking about returning the entities, but just reading them during flow-execution. I all cases Database Mode is Readonly.

More details :

I designed a rulesheet that reads several EDC-managed entities with associations between them. On some of those entities i perform a database-filter. In my flow subsequent rulesheets copy attribute-values from those entities to non-EDC managed entities. At the end of my flow some of the non-edc managed entities are written to the database by means of a SCO. Toggeling between "Incoming/New" and "All" makes my flow fail or succeed. 

I use server-setting : com.corticon.server.restrict.response.rulemessages.only=true
Deploying from Studio or the Deployment Tool does not make a difference.

Is this normal behaviour?