When automating switched controls (such as mutes, plug-in bypasses, or switched controls on plug-ins) Pro Tools treats them as touch sensitive controls. Automation data is written for as long as the switch or button for that control is pressed or touched.
For example, if you have just written a series of mute on/off states on a track in quick succession, the manual method for clearing this automation data would require you to move to the Edit window, choose automation playlist for Mute, select the mute automation data, and delete it. In Pro Tools, this can be done automatically.