https://www.techradar.com/news/google-calls-out-microsoft-regarding-a-flaw-in-windows-10-s-code

Google’s Project Zero team of bug hunters has found a flaw in Windows 10 S, publicly disclosing the issue despite Microsoft wishing to keep it under wraps until it fixed it.

Project Zero looks for exploits in software, either made by Google, or from other companies, and if one is found the team usually alerts the developers of the software in private, giving them 90 days before going public.