Air carrier Captain reported Dangerous Goods documents were issued to the flight crew when no Dangerous Goods were loaded.

Narrative

During preflight we received a Planned Dangerous Goods (DG) Summary showing 1 item in Position *OFF. I informed the FO that it looks like the Dangerous Good has been removed and that there is no Dangerous Goods planned to be on the aircraft. I remarked that there is no need to wait for a Final DG Summary and we will not have to send a DG acknowledgment code.FOM states If DG is loaded; do not release the parking brake until the Final DG Summary is received. With only 1 item listed and it showing a position of *OFF; we assumed that no DG was loaded and we could release the parking brake. After pushback and engine start we received a Final DG Summary. Again; it showed 1 item position *OFF and included a Pilot Notification Form (PNF) showing 0 pieces; 0 weight; dry ice. FOM states: a DG PNF for DG that is shown as OFF" will not be printed.We did receive a printed PNF even though DG was shown as *OFF. It seems that we should not have received a PNF because there was no DG loaded. Dispatch confirmed there was no DG on the aircraft. The Final DG Summary and PNF created some confusion. If we receive a Planned DG Summary showing only 1 item with position *OFF; should we wait for the Final DG Summary and PNF and send a report before releasing the parking brake?Per FOM; if no DG is loaded; neither a PNF nor Final DG Summary is required. So I assumed we could release the parking brake and not have to send a report."