With the information given the assumption of an issue in the model is the most obvious.

Of course it's opinions in the end, as there isn't anything more factual on which to work.

As you are had your RPD inspected by Oracle and had no feedback on changes or improvements your next step is to open a SR and manage it with Oracle in the end. Their tool, their inspection of the RPD and if things still doesn't work as expected up to them to fix it.