Hi Jeff,
Thank you for the update. I am able to recreate this issue with my sample Z series NEF and JPG files. When the IPTC prefs are set to read from the Raw when paired with a Jpeg, the Contact Sheet Label fields are reading from the NEF. Unfortunately the Preview window's Info panel and the Contact Sheet's Show Info Tool Tips, are using the metadata from the Jpeg. I'll file a bug report.
Best regards,
--Bob