porting this with_together loop from ansible 1.9.4 -> 2.0.1.0

Hi,

after upgrading from ansible 1.9.4 to 2.0.1.0
the task[1] shown below fails with the following message:

FAILED! => {"failed": true, "msg": "an unexpected type error occurred.
Error was 'bool' object has no attribute '__getitem__'"}

- name: setup IP list (1/2)
  set_fact:
    ips:
        ipv4: "{{ item.0 }}"
        ipv6: "{{ item.1 }}"
  with_together:
        - "{{ tor_v4ips }}"
        - "{{ tor_v6ips }}"
  register: ipsinterm

tor_v4/6ips are basically:
ansible_all_ipv4/6_addresses facts

Expected behavior:
The loop should not fail even if the host has no IPv6 IPs
(it used to work fine with v1.9.4)

Is this a bug/regression or an expected behavior change?

[1]
https://github.com/nusenu/ansible-relayor/blob/61a4057895a1c98e8b895e75bc1df30033af502a/tasks/ip-list.yml#L3