The thing that makes me chuckle with derision is, is when otherwise clear and careful speakers use the same weird misconstruction as appears in this sentence. It’s amazingly common. You may never have noticed, but once you start listening for it, you hear it everywhere. The thing about that is, is that if you call them on it, they deny having done it. And then they go right ahead and do it again! I suppose it depends on what your definition of “is, is” is.
(Here’s another page about this same phenomenon.)