I posted without comment, thinking it was interesting.
On another thread, it's pointed out that CNN made an error - it was not the microphone, but something in the audio processing going to the speakers in the hall. So what was heard on TV was apparently not affected.
It can't have been very significant. Obviously Holt, Trump and Clinton could all hear and respond to each other, and the audience was admonished more than once to stop applauding comments they liked. I'm willing to bet that if there had been a serious problem they would have paused so the techs could fix it.