What is the ruling on adding an action belonging to the same genus as the prayer elements?

Primary text

If one intentionally performs an addition of the same genus as the prayer components, such as standing where one should sit, sitting where one should stand, or adding a rak'ah or essential pillar, the prayer is invalidated by the intentional act. For forgetfulness (sahw), prostration of forgetfulness (sujud as-sahw) is required, whether the addition was minor or major. This is based on the Prophet's saying: If a person adds or subtracts, let him prostrate two prostrations (Reported by Muslim).