Taco Bell’s plan to outfit hundreds of drive-thrus with an AI voice assistant isn’t going exactly as the chain expected. Dane Mathews, Taco Bell’s chief digital and technology officer, admitted to The Wall Street Journal that the company is re-evaluating where to deploy the tech as customers air their frustrations on social media, and others post videos of their attempts to troll the system, like ordering 18,000 water cups.

“We’re learning a lot, I’m going to be honest with you,” Mathews told the WSJ. “I think like everybody, sometimes it lets me down, but sometimes it really surprises me.”

Since announcing plans to put AI in the drive-thru last year, Taco Bell has deployed the tech in over 500 locations across the US, according to the WSJ. Other fast-food chains are experimenting with AI, too, including McDonald’s, Wendy’s, and White Castle.

Mathews tells the outlet that while the company still plans on pushing ahead with AI voice technology, he’s discovered that using AI exclusively in the drive-thru at very busy restaurants might not be such a great idea after all.