Upload source entitlement schema API results in 400

@colin_mckibben - i am getting this

{“detailCode”:“400.1 Bad request content”,“trackingId”:“7ba00d28374b429fa99a3d622fa09827”,“messages”:[{“locale”:“en-US”,“localeOrigin”:“DEFAULT”,“text”:“The request was syntactically correct but its content is semantically invalid.”}],“causes”:[{“locale”:“en-US”,“localeOrigin”:“DEFAULT”,“text”:“Only a source type, DelimitedFile, supports schema file download”}]}