Size_type value isn't one of the accepted enumerations like regular, petite, plus, big and tall, or maternity.
Pinterest Catalogs's product schema has format and value rules per attribute. This issue is typically: missing a required attribute for the category, an invalid enum value (e.g., 'XL' submitted where 'M, L, XL' is the valid set), out-of-range numbers, or attributes that conflict across the feed.