I'm running puppet 3.4.3 with hiera 1.3.2. I've been tracking this odd bug with my SSH module losing it's service name and lib path on occasion on my clients. I was able to finally reproduce the behavior in master debug mode.
First connected client after start of puppet master.
Debug: Automatically imported sshdconfig from sshdconfig into production
Debug: importing '/etc/puppet/modules/puppet/manifests/init.pp' in environment production
Debug: Automatically imported puppet from puppet into production
Debug: hiera(): Hiera JSON backend starting
*****NOTE: skipped looking for sshdconfig hieradata/module *****
Debug: hiera(): Looking up puppet::env in JSON backend
Debug: hiera(): Looking for data source defaults
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/defaults.json, skipping
Debug: hiera(): Looking for data source xxxxx
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/xxxxx.json, skipping
Debug: hiera(): Looking for data source nodes/xxxxx
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/nodes/xxxxx.json, skipping
Debug: hiera(): Looking for data source environments/production/Ubuntu
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/environments/production/Ubuntu.json, skipping
Debug: hiera(): Looking for data source locations/Slough/Ubuntu
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/locations/Slough/Ubuntu.json, skipping
Debug: hiera(): Looking for data source Ubuntu
Debug: hiera(): Looking for data source common
Debug: hiera(): Looking for data source global
Subsequent client connections.
Debug: No plugins found in subpath '/etc/puppet/modules/sshdconfig/lib' (file / directory does not exist)
Info: 'replace facts' command for xxxxxx submitted to PuppetDB with UUID 6d2c1cb5-3d0e-4339-a848-e1aa010f146b
Debug: Using cached facts for xxxxxx
Info: Caching node for xxxxxx
Debug: hiera(): Looking up sshdconfig::service_name in JSON backend
Debug: hiera(): Looking for data source defaults
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/defaults.json, skipping
Debug: hiera(): Looking for data source xxxxxx
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/xxxxxx.json, skipping
Debug: hiera(): Looking for data source nodes/xxxxxx
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/nodes/xxxxxx.json, skipping
Debug: hiera(): Looking for data source environments/production/Ubuntu
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/environments/production/Ubuntu.json, skipping
Debug: hiera(): Looking for data source locations/Slough/Ubuntu
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/locations/Slough/Ubuntu.json, skipping
Debug: hiera(): Looking for data source Ubuntu
Debug: hiera(): Looking up sshdconfig::sftp_lib_path in JSON backend
Debug: hiera(): Looking for data source defaults
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/defaults.json, skipping
Debug: hiera(): Looking for data source xxxxxx
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/xxxxxx.json, skipping
Debug: hiera(): Looking for data source nodes/xxxxxx
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/nodes/xxxxxx.json, skipping
Debug: hiera(): Looking for data source environments/production/Ubuntu
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/environments/production/Ubuntu.json, skipping
Debug: hiera(): Looking for data source locations/Slough/Ubuntu
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/locations/Slough/Ubuntu.json, skipping
Debug: hiera(): Looking for data source Ubuntu
Notice: Scope(Class[main]): SSH SERVICE NAME is ssh
Notice: Scope(Class[main]): SSH LIB_PATH is lib
Debug: hiera(): Looking up puppet::env in JSON backend
Debug: hiera(): Looking for data source defaults
Debug: hiera(): Looking for data source nodes/xxxxxx
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/nodes/xxxxxx.json, skipping
Debug: hiera(): Looking for data source environments/production/Ubuntu
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/environments/production/Ubuntu.json, skipping
Debug: hiera(): Looking for data source locations/Slough/Ubuntu
Debug: hiera(): Cannot find datafile /etc/puppet/hieradata/locations/Slough/Ubuntu.json, skipping
Debug: hiera(): Looking for data source Ubuntu
Debug: hiera(): Looking for data source common
Debug: hiera(): Looking for data source global