ably in a lesser fashion than how nginx could, it violates a must not clause in Python’s WSGI PEP333, and I have empiric proof that Tim Berners-Lee chokes a kitten every time you do it.
But what’s the alternative? Risk invisibly cached corrupt data for an undetermined length of time? Ditch nginx, which I think is the best HTTP server on this planet despite this debacle? Nah. Both are unacceptable.