I discovered in Sonar X3c that if you load a previously saved pattern from the Step Sequencer and attempt to edit controller data from within the Step Sequencer UI, you will experience UI anomalies; adding data at a step will appear on a different/unintended step; you cannot delete controller data that was added to an unintended step.
 
Can anyone else confirm this behavior?

Here is a related thread. There are bugs that have been noted, but X3d is also scheduled to be released this week.