Why didn't Muhammad do anything during a leap month?

The pre-Islamic Arabs had 354 days in their calendar rather than the 365 days of the solar calendar. To make up this difference, leap months were added once every three years. But this practice was discontinued in the year 629, and the Qur'an even forbids adding leap months (Qur'an 9:36-37). Biographers like Ibn Ishaq record the month in which the events of Muhammad's life took place. Yet, Muhammad is never recorded doing anything on a leap month. Why is this?