@Andrew is in the process of upgrading our various puppetmasters to modern versions. Before he takes the next step (https://gerrit.wikimedia.org/r/#/c/392172/) he is trying to get a grip on the current level of breakage so he can tell what (if anything) is broken additionally by the new parser.
As of November 19th, there are 11 VMs in deployment-prep showing up with puppet errors or failures.
Error: /usr/share/varnish/reload-vcl && (rm /var/tmp/reload-vcl-failed; true) returned 1 instead of one of  Error: /Stage[main]/Cacheproxy::Instance_pair/Varnish::Instance[text-backend]/Exec[retry-load-new-vcl-file]/returns: change from notrun to 0 failed: /usr/share/varnish/reload-vcl && (rm /var/tmp/reload-vcl-failed; true) returned 1 instead of one of 
in hiera, they were missing key between_bytes_timeout to cache::app_def_be_opts
Puppet got disabled as part of T179684
puppet disabled 'Testing changeprop-redis issue T179684' Puppet has been disabled for 5248 minutes
puppet enabled again.
Error: Could not retrieve catalog from remote server: Error 400 on SERVER: You can only use systemd resources on systems with systemd, got upstart at /etc/puppet/modules/systemd/manifests/init.pp:8 on node deployment-mx.deployment-prep.eqiad.wmflabs
Now requires systemd, must be reimaged to jessie or stretch.
can be ignored for now, will be recreated eventually
Can't log into this one; maybe it never finished building. From https://horizon.wikimedia.org/project/instances/5152bd16-e455-402e-829f-57ea4097f4f6/console
Could not retrieve catalog from remote server: Error 400 on SERVER: Could not find data item phabricator_cluster_search in any Hiera data file and no default supplied at /etc/puppet/modules/profile/manifests/phabricator/main.pp:19 on node deployment-phab.deployment-prep.eqiad.wmflabs
The instance has been created on October 26th by @mmodell.
Various apt/packaging dependency issues
The scap package had a wrong version number. See T180935#3774826
deployment-kafka-jumbo-1 and -2
package dependency issues breaking apt