We are facing a similar, intermittent crash, observed in both simulator and real devices. The app is running NISession over MCSession based on the NIPeekaboo sample from WWDC. The crash occurs when the peer exits the session. We've observed it when the peer exits gracefully, using NISession.invalidate(), and when it exits abruptly due to the app being closed. Simulator crash report attached. I can provide a device crash report with similar signature if that would help. simulator.crash - https://developer.apple.com/forums/content/attachment/d0945d7b-4602-4b31-b04c-ce5038db315a

Here it is! Device crash log - https://developer.apple.com/forums/content/attachment/bc131807-d932-4bb1-aa49-67152d63168e

I've checked all the memory debugging boxes. At the Xcode breakpoint, I see references to NSCalendar and locale operations, which don't appear in the crash reports. Thread frames - https://developer.apple.com/forums/content/attachment/a615c248-4c7a-4fb4-819a-1e1e99a17edc

Good news?! I've reproduced the crash using the NIPeekaboo sample from WWDC. Running on two NI capable devices: Accept the permission on both devices so NISession can be established Restart the app on device A (e.g. by relaunching from Xcode) The app will reliably crash on device B Crash signature is the same as we've seen with our own app. iPhone 11 crash log - https://developer.apple.com/forums/content/attachment/d724b6c8-171e-459d-ab33-1be79e5d2fa3

FB8891415 (Application crash on peer reconnect using MultiPeer Connectivity to facilitate a Nearby Interaction session)