Hi pdr469,
When we set format to webinar, it will trigger some backend processes to validate whether the selected webinar configuration and type are valid.
Unfortunately the behavior is by design, there is no supported way for us to disable these processes.
You could disable javascript functions which execute at OnChange event of Webinar Configuration fields to prevent validation, but it may lead to potential issue.


From my test, I will still receive one time error notification(empty credential), but event is able to be saved and go live.
Please create a new main form or modify in a sandbox environment to test.
Regards,
Clofly