A difference in the paperwork rules between the Premier League and EFL was the reason Liverpool's move for Fabio Carvalho collapsed.
The Reds were keen to get a deal done for the Portuguese attacker on transfer deadline day.
A fee had been agreed between both Liverpool and Fulham, and as the clock ticked towards the 11pm deadline negotiations were rushed through to try and get the relevant paperwork and Carvalho's medical done.
Sadly for Jurgen Klopp's side, the deal fell through.
The chief reason is that Premier League clubs are allowed to file a 'deal sheet' that proves a transfer is effectively agreed so long as it is submitted before the 11pm cut-off point.
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It then grants the clubs involved extra time beyond the deadline.
The problem in this instance was that Fulham, as a Championship club, fall under EFL rules and the competition does not have such a process in place.
Therefore, any deal needed to be done before 11pm.
Carvalho, who has played a prominent role in the Cottagers taking the division by storm this term, is out of contract at the end of this season.
That complicates matters in that Fulham would be loathe to lose the 19-year-old for nothing in the summer. A foreign club could effectively approach him on a pre-contract deal without having to pay a fee.
As Carvalho is under the age of 24, Premier League rules state that Liverpool would have been required to pay compensation to the Cottagers if they signed Carvalho at the end of his contract.
If a fee between the two cannot be agreed then the matter would then go to a tribunal, with a final value then worked out.
That was the case between the same two clubs when Harvey Elliott swapped London for Liverpool.
The Reds signed him in 2019, when he was aged just 16, and were later made to pay up to £4.3m for the midfielder.
Carvalho has been a key player at Craven Cottage this season, scoring seven goals and providing four assists in 18 appearances in the Championship.
His manager Marco Silva will now be hoping he can continue that fine form and forget all talk of his future, as Fulham look to seal an immediate promotion back to the top flight.
He also said the club were still trying to get Carvalho to extend his deal.
Silva had said just days ago: "Fabio will be with us until the end of the season.
"From day one I have been trying to keep him. It is not a surprise that clubs are interested in Fabio. We are talking about a young player with big talent.
"The situation is not easy because he is in the last year of his contract, but that is the reality. It is out of our plans for him to leave the club in this window.
"It has been difficult for us to renew with him, but we are trying.
"It is always difficult with a player of this talent - even with a contract it is difficult to keep him, and without it is even worse."
