If you have an automation that is synching with Rally and fields mapped include Blocked and Schedule State or Flow State, you may see a synch failure with the error:
Constraint violation: constraint violation
This happens due to the way that Rally's behavior is to unblock work items that move Schedule State or Flow State
When the source system sends both a Schedule/Flow State change and maintains the Blocked status, an error can occur
This should be resolved in the source system by unblocking the source work item