Internal Server Error with underscore in PluginName

[MisterMike]

When setting up a Craft 3 Module and with a Module Name using an underscore (example used: "k4_Ajax"), there is a Server Error:

Internal Server Error

RecursiveDirectoryIterator::__construct(/home/forge/pluginfactory.io/craft/storage/runtime/temp/pluginfactory/k4ajaxmodule): failed to open dir: No such file or directory

Might be related to issue #64

[khalwat]

This is confirmed a bug