Linfield have queried the Irish FA decision not to sanction Glentoran over the registration of forward player Cameron Stewart.
ast week, Sunday Life Sport revealed that the Association decided to take no action against Glentoran after the Blues flagged up a potential issue with the player's registration.
But Linfield were not happy with the outcome of the investigation, and wrote to the IFA last Monday requesting clarification.
When contacted by Sunday Life Sport, an Irish FA spokesperson initially denied they had received any correspondence from the Blues on the issue, but recanted when told Linfield had received a response from the Association.
Stewart, who was a Linfield player before his current spell at The Oval, played in a Big Two League derby in November at Windsor Park, when the teams shared the points in a 3-3 draw.
Sunday Life Sport has been told a rival team flagged up a potential discrepancy in Stewart's registration on the Comet system used in the Danske Bank Premiership, specifically his date of birth.
The Windsor Park club then contacted the IFA to question Stewart's registration, and it was investigated by the IFA with no action taken.
"The Irish FA Player Registration Sub Committee has considered the matter raised by Linfield FC regarding the registration of Glentoran FC player, Cameron Stewart, and have determined that no further action will be taken," said an IFA spokesperson last week.
But the Blues were seemingly unconvinced by the findings of the committee and pushed for clarification having received a very brief response from the IFA on Friday of last week.
"Linfield felt there were questions to be answered, bearing in mind the League directive that only 20 players over 21 are permitted in first-team squads," said an insider. "They were also eager to know why there was a second profile set up for the player on the system, and asked the IFA for an explanation."
Glentoran harbour suspicions that Linfield's move is partly motivated by a desire to retaliate after the Glens reported Linfield fans for alleged sectarian chanting, which was not proven by the IFA.
Linfield remain tight-lipped on the matter, but Sunday Life Sport understands they will consider their next step at board level within the club.
Had the IFA found Stewart to be incorrectly registered, it is likely Linfield would have been awarded a win from the November encounter.
"The matter has been resolved," said an IFA spokesperson on Saturday night.