Profiles given on command-line not added to exec.additionalArguments

In my POM, I have two distribution management sections, each in a separate profile:

...
    <profiles>
       <profile>
            <id>private</id>
            <distributionManagement>
                <repository>
                    <id>private-repository</id>
                    <url>scp://repository.example.com/opt/mvn/private</url>
                </repository>
            </distributionManagement>
        </profile>
       <profile>
            <id>public</id>
            <distributionManagement>
                <repository>
                    <id>public-repository</id>
                    <url>scp://repository.example.com/opt/mvn/public</url>
                </repository>
            </distributionManagement>
        </profile>
    </profiles>

Running mvn release:prepare -Ppublic puts the following line in release.properties:

exec.additionalArguments=-P default-profile,default-profile

(The profile "default-profile" is the profile in my settings.xml which is active by default.)

If the release plugin was working correctly, this line would be:

exec.additionalArguments=-P default-profile,public

In earlier betas, I believe this worked correctly. The workaround I'm using is to run mvn release:prepare, then mvn release:perform. The second command fails, and I go to target/checkout, and run mvn deploy -Ppublic manually.

Changing release.properties doesn't work, either. It seems like release:perform uses its own list of profiles, not the ones in the properties file.