Sure does feel like OpenAI, a company that for obvious legal reasons needs to know about data provenance, would KNOW whether "de-identified data derived from their usage" was accessed.
OpenAI needs a much better explanation here.
OpenAI’s official statement regarding their interactions with Tristan and Levent:
“We recognize the priority of their work on forced Euler”
“no specific user data was accessed in order to solve this problem”
“we cannot rule out that de-identified data derived from their usage of our products helped improve our models”