I'm currently redesigning an onboarding flow and i've come to this question with an engineer about designing an error message form field box that persists in our fixed header. This would of course be in conjunction with inline error states on the actual field itself.
The form field box will act exactly as many notifications boxes act within a webapp/native app. The only difference is that this will consistently show the user what the issue is until they either fix it or close the box.
I'm curious as to why this isn't done more often and instead the message is moreso always closer to the "submit" or "continue" button.