In 2024, a priest incardinated in the Diocese of London brought forward a complaint that Bishop Fabbro had failed to report an allegation of inappropriate conduct directed towards this priest by a priest not of this diocese.
The complaint was investigated by the Holy See according to the requirements of canon law. At the completion of the investigation, the decision of the Holy See was communicated to Bishop Fabbro that he was not negligent in his office and episcopal responsibilities regarding the complaint.