A giant flag in the stand prevented video assistant referee (VAR) technology from being used to make a ruling on a goal in a Portuguese game between Boavista and Aves on Tuesday.
The Primeira Liga is using the technology this season, but the referee was thwarted by the flag when he attempted to use it to check whether an Aves goal in their 3-0 win was offside.
It was found the flag was obscuring the camera that would have enabled the incident to be checked, meaning the match officials had no option but to stick with their decision to award the goal.
😂 Incredible scenes in the Portuguese League as Boavista conceded an offside goal but VAR couldn't be used due to a giant flag blocking the camera... pic.twitter.com/LjY8nAcEmr— The Sportsman (@TheSportsman) February 7, 2018
The incident comes after a series of problems with the introduction of VAR technology, with Bundesliga players expressing dissatisfaction about it.
Its use in an FA Cup tie between Liverpool and West Bromwich Albion saw two of referee Craig Pawson's decisions overturned in the first half, sparking scenes of confusion as Liverpool were beaten 3-2.
Liverpool boss Jurgen Klopp said he felt the use of VAR would "become a little smoother, more fluent in the future," but West Brom counterpart Alan Pardew criticised the amount of time taken over decisions.
Earlier this month, FIFA chief commercial officer Philippe Le Floc'h told The Associated Press video replays would be used at the World Cup for the first time.
"Definitely VAR will happen," Le Floc'h said. "It's great to have technology in football because this is also a fair[ness] thing."