I read a comment someone posted here that Lisa is related to a tribe which is related to ethnic Cambodians. Obviously Lisa was born in Thailand and is of Thai nationality but ethnic affiliations can cross national boundaries. For example, Kurds.
In the history of SEA there’s many autochthonous tribes. Thai people migrated into Thailand from south China less than a thousand years ago, before that it was inhabited by Khmer (Cambodian) and other groups of people.