Swift: UICollectionView + Custom Segue makes problems - swift

Question

In the following application, I am using an UICollectionView. The text of each cell (string) is downloaded from my SQL-Server. This works pretty well. But somehow, my app sometimes looks as it should, but sometimes not (this happens in simulator, as well as on a native device).
I guess it has something to do with the custom segue I am using, when clicking the settings button (down-right).
#IBAction func settingsButton(_ sender: UIButton) {
// in order to prevent an exception, you have to add an Identity in Main.storyboard
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
// instantiate view controller by storyboard
let nextViewController = storyBoard.instantiateViewController(withIdentifier: "SettingsViewController") as! SettingsViewController
// custom segue
self.performSegue(withIdentifier: "SegueToRight", sender: sender)
// pass email
nextViewController.email = self.email
// switch view controller
self.present(nextViewController, animated:true, completion:nil)
}
Displayed right:
Displayed wrong:

Answer 1

Your problem is probably caused because you are using two different presentation methods, a segue and a present.
Try to remove self.present(nextViewController, animated:true, completion:nil) since the performSegue function will handle the transition for you already.
Also, nextViewController.email = self.email should be set before performSegue to ensure that the data will be passed to the next controller properly.
UPDATE FOR COMMENTS
You need to split your code in two. Inside the #IBAction invoke the performSegue call:
#IBAction func settingsButton(_ sender: UIButton) {
// custom segue
self.performSegue(withIdentifier: "SegueToRight", sender: sender)
}
Then override prepareForSegue:sender::
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let nextViewController = segue.destination as! SettingsViewController
nextViewController.email = self.email
}