So glad to find this thread. I'm experiencing the same issue with the Apple SwiftUI Tutorials (https://developer.apple.com/tutorials/swiftui). I'm using Xcode 14.1. At first I thought I had made a mistake while going through the tutorial, but found the same warning ("Publishing changes from within view updates is not allowed, this will cause undefined behavior.") when running the completed code provided with the tutorial. In this example it seems related to MapKit. Frustrating, but good to know I'm not alone. :-)