authorized_key key path broken?

Today, we updated from ansible 1.3 to 1.4.3

This part of the play worked until now

- name: ensure key files for ssh are present
action: authorized_key
user={{ item }}
key='files/{{ item }}.pub'
with_items:
- user1
- user2

but now, we get those errors

TASK: [common | ensure key files for ssh are present] *************************
failed: [example.org] => (item=user1) => {"failed": true, "item": "user1"}
msg: invalid key specified: files/user1.pub
failed: [example.org] => (item=user2) => {"failed": true, "item": "user2"}
msg: invalid key specified: files/user2.pub

The files are still in the same place. Does this happen on purpose and what is the right way to do this now?

This email looks remarkably similar to a bug report where I asked if you could share your authorized_key file (ideally sanitized) so we could take a look.

If this was yours please comment on the bug ticket.