Harper is alleged to have had his speaker volume too low
Technology used for the referral system is to be reviewed by cricket's governing body after a complaint from the England and Wales Cricket Board.
ECB chairman Giles Clarke has described the International Cricket Council's implementation of the decision review system as "a shambles".
The criticism follows Daryl Harper's umpiring during the ongoing final Test between South Africa and England.
And in response to the furore the ICC is to carry out a full "investigation."
ICC chief executive Haroon Lorgat said: "There is a large amount of controversy, speculation and potentially unfair criticism circulating at present, so it is important to establish the exact facts before reaching any final conclusions.
"These are early days for the decision review system, and so far we are pleased with its effectiveness and the value it can add to the game in support of umpires."
However, he added there had always been "room for further improvement" in the technology.
"This investigation will be conducted in that light so the system becomes even more reliable," he said.
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