One of the Chibok girls kidnapped by Islamist militants Boko Haram chose to stay with her husband instead of being freed, a spokesman for Nigeria's president has said.
She was set to be part of the group of captives who were released on Saturday.
Garba Shehu told local Channels TV that 83 girls were supposed to be freed "but one said: 'No, I'm happy where I am. I have found a husband.'"
The 82 were released as part of a negotiation brokered by the ICRC.
The government agreed to free an undisclosed number of Boko Haram prisoners in exchange.
The militants are thought to be still holding more than 100 of the 276 taken from Chibok, north-east Nigeria, three years ago. The militant group has also kidnapped thousands of other people during their insurgency in the region.
It is believed that some of those abducted have been married to fighters and had children with them.
Parents of the missing Chibok girls are slowly learning if their daughters are among the freed.
The government published the names of the freed girls on Twitter but in Chibok not everyone has access to the social media site.
Mr Shehu said the government was working to verify their identities, so they can be reunited with their families as soon as possible.
Aisha Yesufu, coordinator of the #BringBackOurGirls campaign group, told AFP news agency, that they were working to match the parents to their daughters.