This caused me several hours of misery yesterday, trying to isolate what was going wrong. 

I am unfortunately not at liberty to share the code I'm working on. The example on GitHub has the general thrust of it: my constructor was always called in a specific way, and didn't expect to be given something that was already processed. 

Interesting to see that this is a product of pickling. That makes me think that "fixing" this corner case would probably be a lot of work.

I suppose I should just work around it by checking right away if the input to my constructor has already been constructed!