Or maybe it is because I stupidly left the device selection as my device and not the simulator? Oof.
Here’s a log with the simulator selected, but if you are right and the problem has disappeared I can can extract a clean as shipped Fire and try again.
Sorry about the delay - I was so busy trying to get out the door yesterday I didn’t read things as carefully as I should have. Yes - changing the simulator architecture setting to x86_64 solved things - I am able to successfully debug with the simulator!