Is this good practice to write or its a bug...

Does it work?

I am asking because after 1st example something is broken, and Class::Load::load_class refuses to load NotYetLoadedModule (this differs from require behaviour and thus I filed a bug report)

Well, Class::Load isn't require

The documentation is pretty clear, it uses "heuristics" to determine if a class is loaded, require doesn't do that, so not a bug in Class::Load behaviour ...

its a documentation bug, it should document the actual heuristics, not make an allusion to the origin :)

When I need to load I use the core Module::Load