Do not worry about it not being your "real" code, as long as the issue still occurs.

Replicating the issue in a separate environment and distilling the code down to the minimum required to show the issue is an excellent way to debug. Bugs often become obvious once you have shoveled most of the dirt out of the way.

Unfortunately I don't know too much about ithreads, so one of the more veteran monks will have to step in to help with the details.

One thing I do know is that the error message will be "thread failed to start: blah blah blah", but what it probably means is "thread failed to end cleanly. The thread could have been running for quite some time before it dies and prints such a message.