I am on MacOS 10.15.7 with Xcode 12.4 and I am facing the same problem. Seems to be related to debugging - unfortunately it also applies to the Simulator in my case. This is pretty unacceptable for a 'professional tool' I have to say. I need to get work done (which involves debugging in my case!) Do I need to upgrade to Big Sur? (which probably keeps me busy for another day). Downgrade to 12.2? (Really?!!) What is the quickest way out of it - given I need latest SwiftUI libraries on iOS? (and I guess this is rhetorical question as nobody from Apple seems to care?)

This still seems to be a problem - also on iPad on 14.6 with TrackPad control (MagicKeyboard) and Catalyst on Mac OS 11.4. It works on the iPad Simulator though...

// Never use the cellular interface         let tcp_params = NWParameters.tcp         tcp_params.prohibitedInterfaceTypes = [.cellular]                  if config.useBonjour {             Log.network.notice("Starting NetworkHandler with Bonjour for \(String(describing: config.name), privacy:.public)")                          let endpoint = NWEndpoint.service(name: config.name, type: "_cap._tcp", domain: "local", interface: nil)             nwconnection = NWConnection(to: endpoint, using: tcp_params)         }         else {             let host:NWEndpoint.Host = config.host             let port:NWEndpoint.Port = 5055             Log.network.notice("Starting NetworkHandler for \(String(describing: host), privacy:.public) at port: \(String(describing: port), privacy:.public)")             nwconnection = NWConnection(host: host, port: port, using: tcp_params)         }

Partially Resolved: Once you switch off Metal API Validation it does not crash any more. (But it also does not validate Metal APIs any more...). But what is the point in Metal API validation if it CRASHES the app because of non-existent issues? Is it a regular thing that you need to switch between Schemes when you switch from a physical device to the simulator?

Hmmm.... Wild! I was playing around with my app and stopping now and then and checking for leaks in the Debug Memory Graph. In there some of my objects stayed around much longer than their lifespan and where even flagged as leaked. Looking at the graphs I did see pretty impressive node cycles. Howevery when I continue using the app, these objects seem to disappear and even the 'leaked' objects are gone. Which means the memory graph itself is probably useless? How am I supposed to check if I am having memory leaks or not? I am dealing with pretty large images, so I really need to be sure... Do I need to create a new modelContext to be sure that I get rid of objects I do not need any more?