The error message is:
This was discovered while Ops was trying to upgrade to a pre-release hoyt build.
See the attached tarball for a minimal reproduction. This is an environment that can be untarred into a code dir and verified with puppet apply --debug --noop $CODEDIR/environments/repro/site.pp. The error only occurs when the resource override is in place. If the overridden parameters are inlined into the resource declaration, it works as expected.
According to a bisect, the breaking commit is 38413cd78c61fe34d2ee343ef773a07b4786f65a