Did you have a redirect in your insert or update that would cause a redirect before the email trigger could fire? That is a common mistake. It is thoroughly tested and I suspect your problem is not a bug, but a mistake in implementation.
I'd gladly open up a support incident to investigate what might be going wrong, but you haven't given me enough information to diagnose the cause. I do have that one guess based on the one line of information you actually give about your problem:
"Only sent (triggered) after insert or update and when publish checkbox on submit form is set."
To clearly diagnose a problem with a definite answer, I would need a little more background information. I still don't know that there is a fix for the extension that is necessary in this case.