The masks were a reference to an encounter Warner's wife Candice had with Williams at a Sydney pub in 2007.
For years, the Australians have been the archetypal schoolyard bullies of world cricket, happy to dish it out - but can't take it when the situation is reversed.
The controversy forced Cricket South Africa to issue an official apology to Cricket Austraila and the Australian team, who were angered by the image showing CSA's commercial manager Clive Eksteen and its head of communications Altaaf Kazi grinning with three supporters, who donned the masks.
If there's anything that can be learned from the recent spats between Australia and South Africa's cricketers these last few weeks, it's that our trans-Tasman neighbours are hypocrites when it comes to sledging.
The Australians are understood to be upset that the masks, used as a taunt to specifically target David Warner and his wife Candice, were let into the venue before the photograph surfaced of the two senior executives posing with the fans.
After a spiteful first Test marred by an ugly episode between Warner and South Africa wicketkeeper Quinton de Kock, the Australian opener was in the sights of a small group of South African fans on the opening day of the second Test in Port Elizabeth. He had heavy strapping over much of his left palm which, according to South African players, was aiding him in tampering with the condition of the ball.More news: Samsung targets 43 million shipments of Galaxy S9 duo for 2018
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CSA said Eksteen and Kazi were now subject to "internal processes".
CSA President Chris Nenzani also weighed in on the matter: "On behalf of CSA I extend my honest apologies to the Board of Cricket Australia (CA), its officials, team management, players and their families".
Candice Warner gained recognition in Australia as an "Ironwoman" endurance athlete.
That incident came to light after security camera footage of the players making their way back to the dressing rooms inside the stadium was leaked to the media.
Both Warner and de Kock were penalised for bringing the game into disrepute. Australia's Nathan Lyon also was punished for an over-zealous celebration of a wicket in that first test.
Rabada denies the contact was intentional but faces being banned for the final two tests of the series if found guilty.