Standard library modules appearing as updateable in "Project Interpreter" screen

I created a Python 2.7.12 virtualenv through PyCharm, and as well as the packages I'd expect to see (pip, setuptools, wheel), PyCharm shows the argparse and wsgiref modules in Settings/Project/Project Interpreter, and displays that they have updates available. Pressing "update" does nothing, and I can't seem to make those packages go away -- even though pip didn't install them, and won't touch them since they're part of the standard library and live in /usr/lib/python2.7.

Is there a way to stop PyCharm showing pieces of the standard library as user-installed packages? It's never done this before.