Bug in top-level playbook: tags broken

See the attachment. With ansible 1.7.2 this works as expected:

% ansible-playbook --version
ansible-playbook 1.7.2
% ansible-playbook -i hosts/localhost a.yml --tags b

PLAY [localhost]

(attachments)

x.tar.gz (308 Bytes)

known issue https://github.com/ansible/ansible/issues/9862