UIAlertController pushes navigation bar item - swift

Question

UIAlewrtController pushes the button in my navigation controller down (see image)
Sequence of execution:
on push + the alert controller is activated
on selecting "Take an Action" or "Request an Action" the view controller ActionDetialsVC is activated.
on showing ActionDetialsVC
on back the ActionDetialsVC is closed
The iitial controlers BACK arrow moved
When putting breakpoints on:
self.present (alert, animated: true, completion: nil)
the first Swift instruction in the 2 alert handlers
The strange navigation back button behavior is visible between these breakpoints.
The issue ONLY occurs when introducing Alert Controllers in my views !!!!!
Thank you for your help
Image of the issue:
The code:
func addPressed(_ sender: Any) {
let alert = UIAlertController (title: "Add an Action", message: nil, preferredStyle: UIAlertControllerStyle.alert)
let request = UIAlertAction (title: actionType.Request.Str(), style: UIAlertActionStyle.default, handler: {
action in
self.actionTypeTemp = actionType.Request.Str()
self.performSegue(withIdentifier: "segueActionDetailsVC", sender: nil)
} )
let take = UIAlertAction (title: actionType.Take.Str(), style: UIAlertActionStyle.default, handler: {
action in
self.actionTypeTemp = actionType.Take.Str()
self.performSegue(withIdentifier: "segueActionDetailsVC", sender: nil)
} )
let done = UIAlertAction (title: "Cancel", style: UIAlertActionStyle.cancel, handler: nil )
alert.addAction(request)
alert.addAction(take)
alert.addAction(done)
self.present (alert, animated: true, completion: nil)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "segueActionDetailsVC" {
if let destination = segue.destination as? ActionDetailsVC {
if let action = sender as? PActions {
destination.actionToEdit = action
}
else {
if actionTypeTemp == actionType.Request.Str() {
destination.relatedContact = self.contact
destination.title = actionType.Request.Str()
}
else {
destination.relatedContact = self.contact
destination.title = actionType.Take.Str()
}
}
}
}
}