Referees have got themselves in a lather over what they claim is an incorrect representation of the law on the coin, which was released as one of 29 types of commemorative 50p pieces celebrating the different sports being contested at the London Olympics and Paralympics.
The nifty design on the coin - dreamt up by journalist Neil Wolfson - shows with a few simple symbols what constitutes the offside rule.
Yet referees are arguing that it is incorrect, since 1995 the 'offside' player does not have to be penalised unless he is "interfering with play, or interfering with an opponent, or by gaining an advantage by being in that position".
And some refs are livid at the oversimplification.
"The public will assume this has been thoroughly checked, but sadly it's totally out of date," Referees' Association member Mal Davies told The Guardian.
"On parks pitches it will just encourage players to keep pressurising officials to blow the whistle immediately any time a player is in an offside position - and to abuse them when they don't."
To anybody who is not a referee, it might be pretty obvious that the back of a 27.3mm coin probably isn't the place to debate the intricacies and controversies of the law's application.
And in any case, the coin's designer has rather brilliantly skewered the officials' argument with a piece of logic worthy of a 'Yes, Minister' script:
"With all due respect, I reject Mal Davies's interpretation of the coin (rather than his interpretation of the offside law)," Wolfson said.
"Nowhere on the coin does it say that the 'offside' player is committing an offence — that is a supposition entirely of Mal's creation.
"The coin simply states that the player is 'offside' — which is true, irrespective of whether or not an 'offside offence' results from this scenario."