The Bachelor Nation host shared a behind-the-scenes look at the uncomfortable moment.
"There was no coming back from that," Harrison told ET of the awkward almost-kiss and upsetting aftermath between Clare and Zach. "Clare clearly saw Zach was not the man for her, that was not gonna happen. He was not gonna go further than that. There was no reason to go through with that dinner, there's no reason to put anybody through that dinner."
The interaction, as fans saw, came when Clare leaned in for a kiss at the end of the daytime portion of their spa and pool date. Clare said that Zach didn't lean in and kiss her back, and she then pulled back and retreated to her suite. Zach followed her, attempting to figure out what happened, and grabbed onto her neck several times in the process.
"It's a huge mix-up. Huge!" Zach told the camera after leaving Clare's pool. "I mean, I was trying to kiss her. Just the look on her face, it was the instant -- she was hurt. And that's never my intention. It's just the worst possible thing, and I don't know what else I could have done."
Clare, meanwhile, explained to the camera that she was "triggered" by the way Zach grabbed her after the awkward moment. She has previously spoken on the show this season about being in an abusive relationship in the past.
"Zach just made me feel really uncomfortable. I go in for the kiss to Zach, he pulls away, and the second I just tried to walk away, he grabs me. That kind of triggers me, and kind of scared me," she said. "I didn't want to be near him in that moment. If I want to walk away because I'm uncomfortable, let me walk away." Crawley said she did not want to discuss the incident further.
From Harrison's perspective as a host and producer, there wasn't any reason for the two to continue with the date. "For her to go and fake it, and just not give him a rose, and for Zach to try and put himself out there and try and fix it -- the damage had been done at that point," he noted. "He wasn't getting that rose, so we thought, 'Why do this? Why take advantage of this scene and drag it all out when this guy's just going home?' So I just stepped in and said, let's just be done with this and go on our separate ways."
The Bachelor Nation host also addressed the recent controversy over Clare's social media likes, which seem to indicate that the Bachelorette feels she was "forced out" of her season, in regard to the Tayshia Adams switch previewed in this week's premiere.
"I would just say she has complete control," said Harrison, who explained he hasn't spoken with Clare "for a few weeks now." "This season of The Bachelorette was completely about Clare. It's all about Clare, and she will decide where we go from here. It's totally, completely up to her."
In the meantime, the host is celebrating his new collection with Manly Bands. The partnership was a "no-brainer" for him, given how it aligns with his love of good love stories.
"I do love love. I love weddings. I love when people get engaged. I have seen so many amazing love stories and engagements and I know how hard it is and how special it is to find that," he said. "When Manly Bands came to me and asked if I would be a part of this... I was just excited because they really allowed me to be really involved in creating these rings."
"They are truly incredible quality, you will feel that when you get them, but they really allowed me to create this spectrum where you can find that ring that speaks to you," Harrison added.
The Bachelorette airs Tuesdays at 8 p.m. ET/PT on ABC. (Due to election coverage, next week's episode airs on a special night -- Thursday, Nov. 5 at 8 p.m. PT/ET.)