Leeds have been fined £20,000 for breaching the salary cap in 2018.
The Rhinos said it related to Jack Walker and Luke Briscoe being upgraded to full-time status, as well as hooker Matt Parcell getting a new contract.
An RFL statement said: “It was established during a routine RFL audit that Leeds had failed to declare payments to three players.
“The total amount of the breach was £55,000, with the club found to have exceeded the finite salary cap at four separate points during the season by sums ranging from £10,500 to £25,500.
“Leeds Rhinos acknowledged these errors and reached an ‘Agreed Decision’ with the RFL in accordance with RFL processes, thereby removing the need for an Independent Tribunal.”
Half of the £20,000 fine has been suspended. Earlier this year, Wigan were successful in an appeal against a two-point deduction following salary cap breaches.
They related to six separate payments in 2017 that saw them go over the cap by £14,700 – and they were fined £5,000 plus £2,000 costs.
It is the first time in Super League history that Leeds have been punished – and they join a list that includes Bradford, Halifax, Hull, Salford and St Helens.
Chief executive Gary Hetherington said: “This was an administrative error on our part for which I take responsibility and we are obviously disappointed to lose our 23-year unblemished salary cap compliance record.
“We had no idea we had exceeded the ‘live’ cap at the time and with hindsight we could have averted the breach by loaning out a player to another club.
“Two of the players, Jack Walker and Luke Briscoe, were promoted from part time to full time status during the season and whilst their increased monthly payments were included in our salary cap return to the RFL, we didn’t lodge their new contracts until the end of the season. Matt Parcell also had his contract extended at the start of the season and whilst the increased monthly payments were paid the contract wasn’t signed and lodged with the RFL until the end of the season and those combined breaches created the breach we now accept.
“Managing a Super League club salary cap is, and has always been, a very precise operation and we have now revised some of our internal procedures to ensure we don’t make the same mistake again.”