Works in 3.6.2, breaks in 4.0+

[Daemach]

I recently tried upgrading hyper and it started failing in an odd way. This code works perfectly in 3.6.2. As you can see, the fullURL is dumped right before sending: https://www.screencast.com/t/LGBxDjV2tf

But in 4.x and 5.x, the same code fails like this: https://www.screencast.com/t/HXJaQtzPY