I just created one: https://feedbackassistant.apple.com/feedback/14934250

Actually on the UI the call will be active but you can see the error in the log: Couldn't start Apple Voice Processing IO: Error Domain=com.apple.coreaudio.avfaudio Code=561017449 "(null)" UserInfo={failed call=err = PerformCommand(*outputNode, kAUInitialize, NULL, 0)}

A few more details: Correction: The call won't be active again because the audiosession is not activated. It is important that the call must be finished by the remote participant. Otherwise everything works fine. Test device: iPhone 13 Pro, iOS 17.6.1