This looks for Debian in $operatingsystem not Raspbian. In facter > 2.4.6 (ie >4.0.0) $operatingsystem changes from Debian to Raspbian and breaks the default system provider.
It can't be set by default, at least not in serverless agent setup Maverick is using.
Warning: Found multiple default providers for service: init, systemd; using init
Puppet service provider set here: https://github.com/puppetlabs/puppet/blob/7.9.0_release/lib/puppet/provider/service/systemd.rb
This looks for Debian in $operatingsystem not Raspbian. In facter > 2.4.6 (ie >4.0.0) $operatingsystem changes from Debian to Raspbian and breaks the default system provider.
It can't be set by default, at least not in serverless agent setup Maverick is using.
For now, try to downgrade facter to 2.4.6.