segue创建视图控制器swift的新实例

I have an app with four view controllers. The navigation between 1, 2 and 3 is fine but from view controller 1 you have the option of going to 2 or to 4 (which is my settings) I have a segue from 1 to 4. I then use an unwind segue to get back. but when I use the segue back to 4 it instantiates a new instance of 4. I have an app with four view controllers. The n