Jofra Archer escaped sanction for two waist-high full-tosses marking a controversial end to the second day of the Boxing Day Test between England and South Africa.
The tearaway speedster attempted a couple of slower "knuckle balls" to nightwatchman Anrich Nortje in the penultimate over of the see-sawing day of cricket action.
Nortje, surprised by the flight of the delivery, ducked under both deliveries which evaded his bat and went through to the wicketkeeper.
Square-leg umpire Chris Gaffaney held back signalling a no-ball on the second occasion despite initially gesticulating his arms for the extra.
According to the International Cricket Council playing regulations, a bowler is not allowed to bowl again after delivering two beamers but Archer had a lucky let-off and was given a warning by the umpires.
The on-field officials spoke to the 24-year-old following the completion of his over and decided against suspending him from bowling for the rest of the match.
South Africa skipper Faf du Plessis and head coach Mark Boucher have approached match referee Andy Pycroft to inquire about the seemingly lenient attitude adopted by the umpires.
"The match referee has deferred the situation for comment to the International Cricket Council communications department. We have been asked to leave it to them," a South African team spokesperson was quoted as saying.
Veteran seamer Vernon Philander also shared his thoughts on the incident and hoped the "right call" would be made.
"There was a little bit of conversation going on after the game," he said
"The umpires have to deal with it. Hopefully, they will make the right call."
"For me, it's plain and simple. You are setting an example for the rest of the people looking into this game. You have to make the right call. Are you going to tolerate it at another game or are we going to put a stop to it right here?"
England batsman Joe Denly expressed surprise over Archer's persistence on bowling a slower ball despite one going awry.
Denly, who was stationed at leg slip and would have had a clearer view of the ball trajectory, said the second delivery was within limits and "just missed the stumps".