The Second Circuit has determined that an omission can support an adverse credibility determination when the applicant could have been expected to disclose the information sooner. In this case, the applicant testified during direct examination that he was on a government black list, but did not disclose until cross-examination that his father and church mate (both of whom had submitted letters in support of his claim that were devoid of any mention of the blacklist) could corroborate that his name was on the list.
The full text of Liang v. Garland can be found here: https://www.ca2.uscourts.gov/decisions/isysquery/d68e31ed-8fb2-4fd4-a7a1-1544a38ff6fa/21/doc/18-2257_opn.pdf#xml=https://www.ca2.uscourts.gov/decisions/isysquery/d68e31ed-8fb2-4fd4-a7a1-1544a38ff6fa/21/hilite/