It was alleged by the Broncos, who are now preparing for a preliminary final next weekend, that the Dolphins had attempted to have Mariner break his contract with the club.
The Dolphins were today served with a breach notice by the NRL proposing a $50,000 fine, of which half would be suspended, while Mariner's agent - who has not been named in the notice - would be suspended for 12 months if he breaches any rules within the next two years.
The notice to the player agent makes specific mention of the fact that records of negotiations were not kept.
"The National Rugby League (NRL) today issued the Dolphins with a breach notice following an investigation into the conduct of Dolphins Club Officials and an Accredited Player Agent," the NRL said in a statement.
"Specifically, the breach notice alleges a failure by the Club to comply with the record keeping provisions of the PCR Rules. The notice proposes a $50,000 financial penalty (50% suspended) for the Club.
"The show cause notice issued to the Player Agent alleges a failure to comply with the player negotiation provisions of the PCR Rules and the record keeping provisions of the Agents Accreditation Scheme Rules (Scheme Rules) and proposes a 12-month suspension of the Agent's accreditation should he again breach the Scheme Rules or the PCR Rules in the next 24 months.
"Both parties have 5 business days to respond to the notices."
It was believed at the time that Mariner had asked for a release from the Broncos after dealing with the Dolphins, although eventually added time to his deal at the Broncos.
According to The Sydney Morning Herald, the Dolphins are still maintaining their innocence.
“The club was surprised to receive a breach notice from an investigation that concluded last December and will respond officially to the NRL in due course,” chief executive Terry Reader told the publication.