Problem with import of custom data type state selection

I've created a custom block of data with a field that has a select box for state/province. I need an additional state variable to assign a state to individuals based on information that's not related to their current address.

The problem is that when I upload a CSV of individuals, this created field does not get imported, although the rest of the data on the row does get imported. I've tried this on two different systems running 1.3 and on the sandbox. The import works fine on the two letter state abbreviations for the address of the individual, but not for the custom data segment.