retrieving subsequent fault, where causing fault should appear

The following Topic leads to an Error in RemoteDb:

After setting Unique Key to deferrable initially deferred, ManyValuedAssociation to CascadeTypeAllRemoveOrphan I only got the Exception raised by trying to rollback the transaction:

RemoteDB request error: 
Exception Class: Exception 
Message: Cannot rollback. Database is not in a transaction.

The previous error, that causes the rollback-exception does not appear in my exception-handling:

Exception Class: EPgNativeException 
Message: [FireDAC][Phys][PG][libpq] FEHLER: doppelter Schlüsselwert verletzt Unique-Constraint »uk_135f17b3_...«.
Schlüssel »(x, y)=(4, 2)« existiert bereits.'.

In my opinion only the unique key-violation should raised to our exception-handling.

Isn't this caused by the underlying database connection component?
RemoteDB doesn't do much in addition to what the component does. It just propagates the exception back to client.

Well, that's right, but we do not use any own transactions at this point.
So the internal transaction used by TObjectManager.SaveOrUpdate (or Flush) is hiding the appearing error...

Maybe it's an error in Aurelius combined with RemoteDb.
I was not sure, if I should add this to the existing topic or create a new one...

You can disable TObjectManager automatic transactions by setting the UseTransactions property to False.