Hey,
I have another very strange issue in which a similar call works in the legacy API but in ShipHero it behaves very strangely. I think this is more of a bug. The workaround I am doing for now is a very long formula in NetSuite changing state codes to state names.
Please check request id 5f1afc5478372e6dcd1b6391 to see what I mean. The response looks fine, but in the UI you see what is on the attached screenshot, lower-case “us” instead of “United States” on shipping address. I fixed this by sending the full “Utah” instead of “UT” in the “state” field. Billing address goes through fine using “UT”