I think there is a potential memory leak if stealthy-require is used.

If a non internal module is required Module._load() creates a new Module instance.
The constructor of Module appends this new instance to the parent Module which is the Module where the stealthy require is done and therefore not effected by the post load require cache clean.

Therefore even the stealthy required module instance is removed from require cache there are leftovers in the parent Module.