The Metallica glitch, for which the band has blamed a dead microphone, resulted in Hetfield making a decision to improvise and use Lady Gaga's mic.
Ehrlich has heard a different story from his crew about the problem.
"My guys say that the mic cable was connected," he said. "My guys' theory was that ... one of the extras (on stage) accidentally kicked out the cable that went to the mic."
Still, the end result was Hetfield's singing couldn't be heard for the first part of the performance.
"Obviously, we apologize to the band," Ehrlich said, calling the mishap "awful."
He added that he's worked with Metallica for years, so to see that happen was personally upsetting to him: "You hurt."
In the case of Caesar, the gospel legend, Ehrlich had a better understanding of what happened. When preparing for a clip to run of her for the show, footage of a classic Caesar, Winans and Whitney Houston performance was used, and Winans was mistakenly shown.
Ehrlich said he usually checks such footage but didn't get a chance to this year, since he was busy with the show and the Recording Academy's tribute to the Bee Gees, which taped in Los Angeles on Tuesday and will air at a later date.
"We obviously want to apologize to Shirley Caesar," he said. "It's unfortunate that happened."
Ehrlich was also frustrated that the mistakes have overshadowed some of the great performances that occurred on the show, including Beyonce, Bruno Mars and Adele, who had her own hiccup when she restarted her tribute to George Michael.
"When you do a three-and-a-half hour live show, it's fraught with danger," he said. "It was an adventurous show in many ways."
Ehrlich has produced the Grammys for years and has also produced other events, including the Emmy Awards.