Swift 2协议扩展没有正确调用重写方法

I've been running into an issue using Swift 2's protocol extensions with default implementations. The basic gist is that I've provided a default implementation of a protocol method which I am overriding in a class that implements the protocol. That protocol extension method is being called from a base class, which is then calling a method which I have overridden in a derived class. The result is that the overridden method is not being called.I've been running into an issue using Swift 2's