I’m surprised that you see logs for submission-created.js - as far as I know we don’t currently intend to display logs for any event-triggered function (these in particular: Trigger functions on events | Netlify Docs). Form submissions might be special since the form submission is in essence “sent” to the function, but that is unfortunately working as designed. I have an open feature request to show those logs and have attached this thread to it, so we can report back if the situation changes.
I’ve also marked this thread for discussion with the documentation team to see if we can make it clearer that this is the case, since it has been the case for well over a year now.
Very sorry that you spent time debugging it!