After raising concerns that the business was using ChatGPT data to train Bard, a leading AI researcher is said to have departed Google for OpenAI.

A recent report from The Information revealed that Jacob Devlin, a top Google AI researcher, resigned earlier this year after he warned Alphabet CEO Sundar Pichai and other top executives that the company’s ChatGPT competitor, Bard, was being trained on data from OpenAI’s chatbot. The Information cited a source with direct knowledge of the issue and another individual who had been briefed on it. Devlin believed that the team working on Bard was using information from ShareGPT, a platform on which users publish exchanges they’ve had with ChatGPT. He warned executives that by training on ChatGPT conversations, Bard could end up sounding too similar to OpenAI’s chatbot. Devlin and other Google staff also felt that using the data was a violation of OpenAI’s terms of services.

The Verge reached out to Google and OpenAI for comment, but only received a response from a Google spokesperson who appeared to deny the report. According to the spokesperson, Bard is not trained on any data from ShareGPT or ChatGPT. However, one person told The Information that Google stopped using the data to train Bard after Devlin warned executives about the issue. Shortly after leaving Google in January, Devlin joined OpenAI. He was one of several AI researchers to leave Google at the beginning of the year for competitors.

Devlin, who was at Google for over five years, was the lead author of a 2018 research paper on training machine learning models for search accuracy that helped initiate the AI boom. His research has since become a part of both Google and OpenAI’s language models. OpenAI has hired dozens of former Alphabet staff over the years. Since the company’s chatbot made headlines in November for its ability to do anything from write an essay to provide basic code, Google and OpenAI have been locked in an AI arms race.

Earlier this month, Google released Bard to a select group of users in the US and UK. But Google’s haste to catch up with OpenAI hasn’t stopped there. The Information reported that Alphabet’s two AI teams, DeepMind and Google Brain, have joined forces to better compete with OpenAI.