I'm sorry for the delay but I'm more then happy to manually patch this. The next version should be out within the next few weeks but even so, it would be beneficial to confirm my fix works for you given the wait. Please PM login details if you want me to test the patch.
I'll need a few weeks before I can even send out any quote.
If a new custom feature is built into the app itself. I generally will update it for that IPB version it was made for. So for example, a new feature will be supported for as long as IPB4 is around.
Do you get the same issue when only setting the submit wait in the form itself? i.e. leaving the group permissions empty. It sounds like there might be a number limitation in the group permissions but I'll need you to confirm that by checking the form submit wait time.