The Second Circuit, joining the 1st, 5th, 8th, and 10th Circuits, decided that the BIA may find that an immigrant waives an argument when he doesn't raise it before the Immigration Judge. In the instant case, the immigrant tried to argue to the BIA that the Supreme Court's decision in US v. Descamps impacted the analysis of the immigration consequences of his criminal convictions. However, Descamps was decided before his last immigration court hearing, and he did raise the argument before the Immigration Judge. Thus, the BIA properly deemed it waived.
The full text of Prabhudial v. Holder can be found here: http://www.ca2.uscourts.gov/decisions/isysquery/d7e4e4e1-e7ad-4ebd-9d8e-54cbd67f9f60/1/doc/14-4574_opn.pdf#xml=http://www.ca2.uscourts.gov/decisions/isysquery/d7e4e4e1-e7ad-4ebd-9d8e-54cbd67f9f60/1/hilite/