The conclusion of that study was that when benchmarking LLMs for coding ability, they should not have access to Internet, if you want to know their intrinsic abilities.
Moreover, this can be worrisome as a more direct copyright infringement than the one caused by training, because even if they find open source code on the Internet and they insert it in the generated files, it is pretty certain that it must have had a license that prohibits the removal of the copyright notice.
Can you find the thread?
https://news.ycombinator.com/item?id=48045174
The study paper:
https://arxiv.org/abs/2605.03546
Look at Table 3, where the cheating rates of Claude Sonnet, Claude Opus and Gemini were between 20% and 36%, during the coding benchmarks.