"The NEXUS card will be recognized by the Global Entry kiosks in Canada Preclearance locations only. When using the Global Entry kiosks in Canada Preclearance locations you can use your passport, U.S. Lawful Permanent Resident card or NEXUS card. You cannot use your NEXUS card at Global Entry kiosks outside of Canadian Preclearance locations. At all other ports, you will need to use your passport or U.S. Lawful Permanent Resident card. " https://www.cbp.gov/travel/trusted-t...sked-questions

They either changed the rules or it's a system error.