title: Rewind segue doesn’t trigger viewdidappear
body: <p>As the title goes, I have 2 view controllers connected by 2 buttons. On the first view controller, it modally segues to the second view controller via a button. On the second view controller, there is a button that updates a global variable, and another button that rewinds back to the original view controller. 
  On the first view controller in my ‘ viewdidappear’ function, is an update of a label determined by a variable ( the same global variable changed in the second view controller ). 
  When the second view rewinds back from the second one, it’s as if the viewdidappear function didn’t run at all, and the label did not update. 
  Weirdly in my program there is a 3rd view controller that rewinds back to the first one, and had no problems what so ever updating labels in its viewdidappear function. </p>
  
  <p>If anyone can shine some light on what is happening, it would be greatly appreciated. </p>