We're seeing something very similar in our app; still trying to run it down. John, how on earth did you figure out that your UIColor extension was triggering this behavior? :P

We are seeing the same issue here. Our library's SwiftUI preview stopped working as soon as we included another library. :(

We are seeing similar issues. Our state values are also coming back incorrectly within the .sheet block. Most peculiar! Notable: changing from a sheet to a popover allows our code to run again. Definitely feels like an Apple bug. Let's submit radars! (FB8689560 here.)