[AC-6474] iOS building is broken with XCode 11 with app not opening in simulator

I've just updated to XCode 11.3.1 from 10. Building is broken. Running eg $appc ti build -p ios --target simulator --device-id A9CE58D6-A89D-47B8-9937-F102740EA2E5 (this is the sim for an iPhone 7 running iOS 13.3) There are 2 problem scenarios. Scenario 1 What happens is that the simulator opens and console is left at: [INFO] Finished building the application in 36s 78ms [INFO] Launching iOS Simulator But if I go to the simulator and then choose the device from the Hardware > Device.... menu the actual device window then opens AND launches the app and the console carries on logging as normal. Scenario 2 The terminal finishes after: [INFO] Launching iOS Simulator and returns to the $ prompt. Nothing then will start the app. So in other words the chain is broken somewhere and in Scenario 1 opening the simulator by hand kickstarts it into action. I see there have been lots of problems with XCode 11 (or incompatibilities between SDK versions and XCode) and I did review them but don't see this particular problem. This happens with Ti SDK 8.1 and 8.3. I thought it might be a node problem so tried updating from node 8 to 10 but seemed to make things worse (previously I had only scenario 1, now I have scenario 2).