Email exists error is triggered after the email and phone verification

Product Feedback
1

Auth0 User behaviour:

  1. We have Universal Login, Flexible Identifiers, and Idenitifer-First login enabled.
  2. We have enabled both email and phone for signup.
    Workflow:
  3. The user enters email and phone
  4. user verifies the email via code
  5. user verifies the phone via code
  6. user enters the password
  7. Auth0 throws the error there is an existing account with the same email.
    Please see the attached screen shots.
    If the user enters the existing email/phone number on the step #1, Auth0 throws the error when the user submits the password on the step#4.
    This is a bad User experience. User does not know error. He does not know he has to click the back button and restart again from the initial email and phone screen.

One more use case
We want to collect an additional custom field identifier on the step#1 and validate it using pre-registration action before asking the user to verify the email OR Phone.

Auth0 pre-registration action is triggered once the user submits the password ( step#4). Is there a way we can validate the additional field ( e.g., third party ID) on the step#1