The Ninth Circuit has determined that if an employer filed a labor certification prior to April 30, 2001, but substituted a new beneficiary of that certification after April 30, 2001, that beneficiary is not grandfathered under section 245(i) of the Immigration and Nationality Act. In so doing, the court deferred to the regulation at 8 C.F.R. 1245.10(j), finding it to be a permissible interpretation of the ambiguous statute found in section 245(i) of the Immigration and Nationality Act.
The full text of Valencia v. Lynch can be found here: http://cdn.ca9.uscourts.gov/datastore/opinions/2016/02/02/13-70414.pdf