Pretty recently there was a change that means that our user interface (when you login to an account) maps the "state" field to the state you see for a contact, but the 'state_code' field is not apparent when you view the contact by logging in.
Is that what you're seeing? If so, I'd recommend using the 'state' field instead of 'state_code' to correct the issue. I'm sorry for the inconvenience.
Partner API Support Engineer
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