After being shown a yellow card for dissent by referee Daniele Minelli in the last minute of Pescara’s 1-0 defeat the former Portsmouth and Sunderland midfielder Muntari walked off the pitch in protest.
But the 32-year-old had been trying to the official explain to that a group of Cagliari fans had been allegedly racially abusing him.
The booking was Muntari's fifth of the season and he will now be forced to sit out a game while a statement on Serie A's official website confirmed authorities had made the decision "not to take sanctioning measures against Cagliari".
The statement claimed "only 10 supporters, and therefore less than one per cent" of fans were directly involved in the incident.
World footballers' union FIFPro has called for the yellow card dished out to Muntari - who only joined Pescara in January - to be rescinded.
In a written statement, FIFPro said: "We urge the Italian authorities to hear Muntari's version of events, investigate why the situation was mismanaged and take firm action to ensure this never happens again.
"FIFPro believes Muntari's yellow card should be rescinded. Muntari was well within his rights to approach referee Daniele Minelli, as the first point of reference, to make his grievances known and seek a solution.
"Players should feel comfortable bringing any issue to the attention of the referee, especially one as significant as allegations of racism in the workplace.
"No player should ever feel the need to take matters into his own hands, as Muntari clearly felt obliged to do, by abandoning the match or taking spectators to task for inappropriate behaviour.
"Professional footballers should expect to be adequately protected by the relevant authorities in a place of work that does not tolerate discrimination of any kind."
Speaking to Italian television after the match, Muntari said he had been abused by a group of fans in the first half but had tried to defuse the situation by giving one of the group, a child, his shirt "to teach him you're not supposed to do things like that".
The former Inter and AC Milan star, who also played 84 games for Ghana between 2002 and 2014, said the abuse continued in the second half so he tried to speak to Minelli.
Muntari said: "He told me that I'm not allowed to speak to the fans. I asked him: 'But didn't you hear?"'
"I told him he should have had the courage to stop the game. The referee's not just there to stand on the pitch and blow his whistle - he has to manage everything. He should also listen out for that kind of thing and set an example."
The Italian sports judge also decided that a section of Inter Milan's stadium is to be closed for one game after Napoli defender Kalidou Koulibaly was racially abused on Sunday.
One home section of Lazio's stadium is also to be closed for one game after Roma defender Antonio Rudiger was racially abused over the weekend. Both closures are suspended for one year.
Additional reporting by the Press Association