Dispositions can contain more than one action. For example, Close, Add to object, and so on. However, when a precondition error occurs, the alert action history does not capture all of the disposition actions in the database. (Note that the disposition should always be logged in the database in its entirety.)
A precondition error can occur if the server-side call to add an alert to a case is delayed and you prematurely check the alert in.