This is a really good question. I’m going to take a note on this to checkout. We definitely want to make sure MemberStack respects form validation.
For now, you could use our JS method updateProfile to update the profile info. So you would do your validation, and if all good, use the JS method to do the updating.
Here’s a link to the docs that contain that method.
@belltyler any update on this one yet? My client has observed its bypassing postcode validation on our signup process which is becoming a “thing” for them!