Since upgrading to puppet agent 6.7.0, mail alias has been failing

Hi, since upgrading to puppet agent 6.7.0 (and puppet server 6.5) mail alias has been failing for me.

I've been using this https://github.com/puppetlabs/puppetlabs-mailalias_core module.

I am getting this error:

Error: Could not prefetch mailalias provider 'aliases': Could not parse line "root: root@miraheze.org" (file: /etc/aliases, line: 2)

Error: Failed to apply catalog: Could not parse line "root: root@miraheze.org" (file: /etc/aliases, line: 2)

with the contents being:

1. HEADER: This file was autogenerated at 2019-07-25 15:11:46 +0000

1. HEADER: by puppet.  While it can still be managed manually, it

1. HEADER: is definitely not recommended.

root: root@miraheze.org