Perhaps you are remembering this incident (which involved Equation Editor, a component of Office): https://www.bleepingcomputer.com/news/microsoft/microsoft-app

Perhaps you are remembering this incident (which involved Equation Editor, a component of Office): https://www.bleepingcomputer.com/news/microsoft/microsoft-appears-to-have-lost-the-source-code-of-an-office-component/ https://www.bleepingcomputer.com/news/microsoft/microsoft-ap...