An appeal against the sentence given to loyalist supergrass Gary Haggarty for more than 500 offences including five murders may not be able to go ahead.
The Public Prosecution Service may have missed a legal deadline for lodging its challenge.
But it's been revealed the 60-page PPS submission was lodged after a 28-day deadline to appeal the tariff elapsed.
The court service closes for business at 16:00, but the papers were not served until 16:25 GMT on Monday.
Lord Chief Justice Sir Declan Morgan is to convene a special sitting of the Court of Appeal to rule on whether the challenge can proceed.
The development is potentially a huge embarrassment for the PPS.
A solicitor representing Gary Haggarty said he had challenged the legal basis of the appeal.
"Upon notification that the application was apparently lodged a full 25 minutes after close of business, we queried with Court Service whether in fact a proper and fully compliant appeal had been lodged in this case," said Ciaran Shiels.
"We have been advised that the lord chief justice is to convene the Court of Criminal Appeal on 9 March to consider whether there has been proper compliance with the statutory requirements in respect of this case."
The PPS (Public Prosecution Service) has written to lawyers representing families of victims of Haggarty's UVF gang informing them about the issue.
"An issue has arisen as to whether the notice was served in time," it said in a letter.
"It is the prosecution position that the statutory time limit has been met."