BTW I do know what's causing your issue and how to work around it. But again, please open a new thread so it can be properly indexed for later searches.
Fixed it by changing the URL in the form embed code to our custom subdomain. Not sure why that was an issue but it works fine now
If you test more you'll find that isn't the solution.
(And also, the people that originally posted in this thread may not even have active accounts anymore.)