In some cases, your controllers may fall out of sync.  This can happen when shutdown procedures are not followed either due to a power outage or some other anomaly.  This can manifest itself in many ways through the system.  Often when a problem is intermittent and appears in different locations throughout the system.

To re-synchronize the controllers,

1. Note the controller the system is currently running on.
2. Power the system down.
3. Remove the controller the system isn't running on.
4. Power the system up.
5. Wait for the system to boot completely with the single controller.
6. Insert the second controller.

The controllers will re-synchronize once the second controller is installed.