Returning values from a PL/SQL DA into Multiple Selects Lists Itens with Cascading Lov Parent

Oh, Huge title!

Ok folks, I'm having some trouble with Select List Item and DA.

Example:

     Dynamic Action: when change item P1_A is not null

     Execute PL/SQL:

          begin

          select b,c

              into :P1_B, :P1_C

             from table

           where field = :P1_A ;

          end;

------------------------------------------------------------------------------------------

The fields P1_A, P1_B , P1_C are Select List Itens;

The fields P1_B , P1_C contains Cascading Lov Parent Itens;

- P1_B Cascading Lov Parent Itens: P1_A

- P1_C Cascading Lov Parent Itens: P1_A, P1_B.

Ok... The problem is...

When the DA is triggered, values from query into DA is returned on Field P1_B, but P1_C isn't...

Now, if manually selected P1_A value, then P1_B is refreshed, so I select P1_B value, then P1_C is refreshed, so there are values on P1_C to select.

That process is not working when is used Dynamic Action pl/sql.

I really don't know if it's something to fix on Oracle Apex or it's my fault.

Thank you.