A clarifying note (I hope); when I wrote "Breakpoints work as expected on an app started in Xcode 13.1." I meant apps that I started development on Xcode 13.1. Breakpoint work normally in this case; it's only debugging apps written on earlier versions of Xcode that give me this problem.

I think I can add screenshots only by answering (I'm no expert at these forums), so here goes: Screenshot of the code before starting the app in a simulator: Once the app is running in the simulator:

I'm the original poster on this question. I wish I could give you an answer, but I cannot. The situation I originally described corrected itself; I can't tell you what was wrong or what fixed it. I have seen the same behavior a couple times since, but again, it seemed to resolve itself. Apple tech support was of no help. I wish you luck in finding a solution and please post it if you find one.