Stump microphones picked up and broadcast Buttler calling Philander a "f***ing knobhead" after the bowler stood his ground rather than get out the way of a return throw from Joe Root at mid-off, before adding "get past that f***ing gut", an apparent reference to Philander's weight. Sky Sports apologised on-air for the outburst shortly after it was broadcast.
But Buttler was only found to have breached Article 2.3 (Use of an audible obscenity) of the ICC Code of Conduct for Players and Player Support Personnel, rather than Article 2.13 (Personal abuse of a player).
Buttler was fined 15 percent of his match fee and handed one demerit point, but would have been in line for a more severe sentence if the umpires had judged his conduct to have constituted "language of a personal, insulting, obscene and/or offensive nature" directed at Philander.
The incident was played down by Joe Root after the game.
"I don't think it was anything serious," Root said. "It was just two guys playing hard Test cricket. Emotions were running quite high and I don't think anyone overstepped the mark. You want a bit of spice on the TV anyway, don't you?"
Buttler admitted the offence and accepted the sanction proposed by Andy Pycroft of the Elite Panel of ICC Match Referees, meaning there was no need for a formal hearing.
He was given one demerit point and an official reprimand in October 2016 following a confrontation with Mashrafe Mortaza and Sabbir Rahman, but that offence was committed more than 24 months ago, meaning it has been wiped from his disciplinary record.
Level 1 breaches carry a minimum penalty of an official reprimand, a maximum penalty of 50 percent of a player's match fee, and one or two demerit points.