hdf argument linter generating possibly incorrect warning messages

Running:

hhvm --config-value hhvm.log.runtime_error_reporting_level=8191 phpinfo.php
Possible bad config node: hhvm
....

The "Possible bad config node" message comes from within the guts of Hdf::lintImpl when the complement of hdf_is_visited is propagated up the hdf hierarchy, with some overly clever coding to prune away children. The child that is added to the report vector is hhvm.log.runtime_error_reporting_level, but the ".log.runtime_error_reporting_level" is effectively discarded by the time the recursive lintImpl does its thing.

I'm wondering if the linter is run prematurely (eg, before the CLI arguments are acted on), or if this --config-value syntax isn't right anymore. Or perhaps this is vestigal brokenness from the days when hdf was the main way configs were handled.