dbm-update does not work for changelog.xml (but does for changelog.groovy)

$ grails create-app test
$ cd test
$ grails install-plugin database-migration
$ grails create-domain-class org.example.Book
$ grails compile
$ grails dbm-generate-gorm-changelog changelog.xml

environments {
    development {
        dataSource {
            driverClassName = 'com.mysql.jdbc.Driver'
            username = 'username'
            password = 'password'
            dialect = org.hibernate.dialect.MySQL5InnoDBDialect
            url = 'jdbc:mysql://localhost/test'
        }
}

$ grails dbm-update
$ mysql test -e "show tables"
+-----------------------+
| Tables_in_test        |
+-----------------------+
| databasechangeloglock |
+-----------------------+

$ grails dbm-generate-gorm-changelog changelog.groovy
$ grails dbm-update
$ mysql test -e "show tables"
+-----------------------+
| Tables_in_test        |
+-----------------------+
| book                  |
| databasechangelog     |
| databasechangeloglock |
+-----------------------+