I’ve had a request from Puppetlabs, and as there’s no need for a security embargo on this, I’m opening it up here for discussion (and will be inviting them to join the discussion). Here’s the detail:
(Trimmed for brevity, I’m sure someone will correct me if I missed anything)
@packaging could you comment on this? I’ve no idea of the impact 
IMHO this isn’t really a packaging issue. If this is not supported, I think a check could be added to https://github.com/theforeman/puppet-puppet/blob/master/manifests/agent.pp. This would probably be if $puppet::version == 'latest' && $puppet::package_provider == 'chocolatey' { fail('unsupported') }.
<rant>Given the huge complexity of the puppet_agent module and how it’s tied to Puppetlabs repository URLs I understand people don’t want to use it. It needs more parameters for those who install Puppet RPMs from their internal mirrors for example. Given how much effort it takes to get patches merged into Puppetlabs modules I haven’t bothered to try and add these but recommended alternative ways of upgrading. Our installer dependencies on puppetlabs/{apache,mysql,postgresql} prove enough of a challenge already.</rant>