There is a lot of encoding issues surrounding the use of win32/registry.rb from Ruby v2.1 and above. Prior to 2.1, there was some craziness, but it didn't affect us in a negative way. The recommendation is that we stop using that and instead make the calls to the registry directly using FFI.
Quite a bit of background is on the PR for
PUP-3779 - https://github.com/puppetlabs/puppet/pull/3459#discussion_r22838455
The issues surrounding ruby's win32/registry.rb could also impact:
- registry module
- Any custom facts that make registry calls