I have developed my first App with iOS 13 as the target. I use a split-view controller and from the "Detail page" of that Split-view, I segue to 4 other ViewControllers ("Present Modally"). The Unwind from these are buttons Cntrl-Dragged to Exit, where I select a function present in the SplitView Controller. From the "Master page" of the split-view, I segue ("Present Modally") to 3 different Navigation Controllers, each of which contains a "normal" ViewController (embedded just to easily get the top bar). The Unwind from these 3 ViewControllers is done in the same way described above.All of this works great in iOS 13. Some potential customers asked to support iOS 12 (which I have never developed under). I didn't have to make too many changes to do this, but I seem to have missed something.The Unwinds from the first four segues continue to work just fine.The Unwinds from the last three segues don't work at all. The user is stuck viewing those pages forever. (Yes, on a real device; not just the simulator.)Looks like there are two differences here: Detail vs Master page as the origin, and the use of Navigation Controllers on the failing cases. Any insights greatly appreciated! Barry