Cuban seed names the parent, not the field. After the embargo, growers took Cuban seed to Nicaragua, Honduras, the Dominican Republic, and elsewhere. Habano, corojo, criollo, and related names sit in that family. The plants see different soil and rain. The cigar is a Nicaraguan or Honduran or Dominican cigar unless it was grown and made in Cuba.
Padrón describes its leaf as Cuban-seed, sun-grown, Nicaraguan. That is a seed claim plus an origin claim. Both can be true at once.
Do not read “Cuban-seed” as a loophole around the word cuban cigar. The island and the seed went different ways after 1959.