messageID is undefined when using unbind()

When I bind like this:

$ldap = Net::LDAP->new( $dshost , onerror => 'warn' );
$ldap->bind( $dn, password => $password );

Unbinding like this:

$ldap->unbind();

Makes my script generate this:

messageID is undefined at /usr/lib/cpan/Net/LDAP/Message.pm line 195.

This happens with perl-ldap 0.49.

It did not happen with 0.44.

Is this a known behavior?

jd