Concat module: uninitialized constant Puppet::Type::File::Owner

On puppet 4.5.1 using puppetserver 2.3.2 with the concat module 2.1.0, I periodically get the following errors on my master:

Could not autoload puppet/type/concat_file: uninitialized constant Puppet::Type::File::Owner

It seems to flip back and forth between fail and succeed, though I don't think its ever failed when running puppet agent -t in the foreground. This show up in our puppetboard.