State/Province field is mark as optional but purchasing product will throw error if that's the case

Summary

Customer registered account on customers portal and the State/Province was not select because it said Optional but got an error while trying to purchase a product.

Steps to reproduce

  1. Register an account on customers portal
  2. Leave the State/Province unselected
  3. Proceed to buy a plan
  4. Observe the error message State/Province should be ISO standard state or province. userdata: NULL is not an ISO state/province of United States.

What is the current bug behavior?

Customer cannot make purchase because the State/Province was not selected.

What is the expected correct behavior?

Either customer is able to make purchase without selecting State/Province or the field should not be marked as optional.

Relevant logs and/or screenshots

Screen_Shot_2020-04-11_at_7.47.41_PM

Workarounds

Fill in the State/Province field

Reported examples

  1. https://gitlab.zendesk.com/agent/tickets/153215