Instacart, the grocery delivery service headquartered in San Francisco, is addressing claims that it has been charging different prices to different customers for the same products. These allegations have arisen from findings suggesting that the company conducted an experiment using artificial intelligence to adjust prices.

The claims come from a study by Consumer Reports, along with the advocacy group Groundwork Collaborative and the non-profit news outlet More Perfect Union. According to their research, Instacart’s app presented varied pricing for identical items to different customers, with some prices reportedly differing by as much as 23%.

In a summary of the study, Groundwork Collaborative accused Instacart and similar companies of “developing, acquiring, and refining technology to conduct pricing experiments on a large scale.”