A glitch caused ChatGPT to go 'mad' by responding to user prompts in gibberish, resulting in a rash of complaints. 

Users across the world took to social media to share nonsensical responses generated by ChatGPT over a period of several hours, including 'the cogs en la tecla might get a bit whimsical. Muchas gracias for your understanding, y I’ll ensure we’re being as crystal clear como l’eau from now on” — or getting stuck in infinite loops — “A synonym for “overgrown” is “overgrown” is “overgrown” is “overgrown” is “overgrown” is “overgrown” is “overgrown” is “overgrown."'

OpenAI did not reveal what the issue was or why it was happening, though reports attributed the problem to a data training upgrade to GPT-4 Turbo in December 2023. 

OpenAI later said it had fixed the issue.