Adobe Analytics Update Classification APIs not classifying data in reporting suite

We are currently attempting to migrate off of using the Adobe Data Connector and Genesis APIs to update classifications for reporting suites in Adobe Analytics. We are attempting to use the Create/Populate/Commit Import APIs (https://github.com/AdobeDocs/analytics-1.4-apis/blob/master/docs/classifications-api/methods/r_CreateImport.md) however upon submitting data to the reporting suite, we see it classified as `unspecified`. Any help here would be appreciated. This is a large blocker in being able to migrate off the soon to be deprecated Data Connector and Genesis APIs.