Unexpected inserts sent to NSFetchedResultsController - ios

Question

I have a model with Managers and Employees. Managers have a relationship to employees. I have a UITableViewController utilizing FRC. The FRC is initialized over the Manager model with a sort descriptor on the name.
The normal things work - adding managers and deleting managers work as expected. However, what's strange is that when an employee of an existing manager is updated (changing some coredata property on employee), FRC sends an insert on the manager of the employee being updated. CoreData obviously gets confused, and reports an assertion:
CoreData: error: Serious application error. An exception was caught
from the delegate of NSFetchedResultsController during a call to
-controllerDidChangeContent:. Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section
after the update (8) must be equal to the number of rows contained in
that section before the update (8), plus or minus the number of rows
inserted or deleted from that section (2 inserted, 1 deleted) and plus
or minus the number of rows moved into or out of that section (0 moved
in, 0 moved out). with userInfo (null)
The strange thing is that in the assertion, it seems to think that 2 inserts were performed with 1 delete. I logged the didChangeObject and I only see a single insert.
Why is an insert being sent for the Manager when it's employee is updated?
Update - showing the code
Here's my view controller's initialization of FRC. Note that I'm modeling companies, so managers belong to companies (which explains the predicate:
let fetchRequest = NSFetchRequest(entityName: "ManagerModel")
fetchRequest.predicate = NSPredicate(format: "%K == %#", "company", self.currentCompany)
fetchRequest.sortDescriptors = [NSSortDescriptor(key: "name", ascending: false)]
Here's my view controller's didChangeObject function:
func controller(controller: NSFetchedResultsController,
didChangeObject anObject: NSManagedObject,
atIndexPath indexPath: NSIndexPath?,
forChangeType type: NSFetchedResultsChangeType,
newIndexPath: NSIndexPath?)
{
let manager = anObject as! ManagerModel
switch(type)
{
case NSFetchedResultsChangeType.Insert:
log.info("Inserting row at index path \(newIndexPath!), \(manager.name)")
break
case NSFetchedResultsChangeType.Delete:
log.info("Deleting row at index path \(indexPath!), \(manager.name)")
break
case NSFetchedResultsChangeType.Update:
log.info("Updating row at index path \(indexPath!), \(manager.name)")
break
case NSFetchedResultsChangeType.Move:
log.info("Moving row at index path \(indexPath!) to \(newIndexPath!), \(manager.name)")
break
}
}
My code syncs data and updates data. Here is the code that updates the employee by first searching for it.
let cdEmp = cdMgr.findEmpoyeeById(mailId: downloadedEmp.empId)
if (cdEmp != nil)
{
// If I don't update the cdEmp model, I have no problems.
// If I update any of the cdEmp properties, I'm getting
// the insert notification on the manager instance cdMgr
cdEmp!.name = downloadedEmp.name
}