These codes below are one example the exception occurs.
以下は、それを再現する一例です。
class TableViewReloadViewController: UITableViewController {
    
    private var didReload = false
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.tableView.estimatedRowHeight = 10
        self.tableView.rowHeight = UITableViewAutomaticDimension
    }

    // MARK: - Table view data source

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 2
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        print("@@@ numberOfRowsInSection. section=\(section)")
        switch section {
        case 0:
            //let count = 1
            let count = self.didReload ? 2 : 1 // [*1]
            print("@@@ numberOfRowsInSection. section0. count=\(count)")
            return count
        case 1:
            let count = 1
            //let count = self.didReload ? 2 : 1 // [*4]
            return count
        default:
            return 0
        }
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        print("@@@ cellForRowAtIndexPath. section=\(indexPath.section)")
        switch indexPath.section {
        case 0:
            let cell = tableView.dequeueReusableCellWithIdentifier("cell0", forIndexPath: indexPath)
            return cell
        case 1:
            let cell = tableView.dequeueReusableCellWithIdentifier("cell1", forIndexPath: indexPath)
            if !self.didReload {
                self.didReload = true // [*2]
                dispatchAsyncMain({
                    print("@@@ reloadRowsAtIndexPaths. section=\(indexPath.section), row=\(indexPath.row)")
                    // NOTE:
                    //  This exception below occurs.
                    //  ```
                    //  *** Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-3318.16.14/UITableView.m:1582
                    //  *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0.  The number of rows contained in an existing section after the update (2) must be equal to the number of rows contained in that section before the update (1), plus or minus the number of rows inserted or deleted from that section (0 inserted, 0 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).'
                    //  ```
                    //
                    //  ## There was caused that,
                    //  1. The [*1] count = 1. (section: 0)
                    //  2. The [*2] didReload changes from false to true.
                    //  3. The [*3] reloadSections executes. (section: 1)
                    //  4. The [*1] count changes from 1 to 2. (section: 0)
                    //  5. The exception occurs.
                    //  * If you implement [*4] instead of [*1], the exception doesn't occurs.
                    self.tableView.reloadSections(NSIndexSet(index: indexPath.section), withRowAnimation: .Fade) // [*3]
                })
            }
            return cell
        default:
            return UITableViewCell()
        }
    }
}