It looks like the issue is that the root logger is missing from the manager's loggerDict.

A suggested fix is to change the creation of the loggerDict in the Manager class:

-       self.loggerDict = {}
+       self.loggerDict = {rootnode.name: rootnode}

This may have been omitted from the initial design to avoid reference cycles; however, with the advent of garbage collection this should no longer be an issue.  Alternatively, a weak reference could be used.