That sounds like another bug! Would you file that in bugzilla with some details of how you logged in and what the result is? I was able to reproduce it with a test github account, so you're not alone :)
That doesn't seem terribly strange, since that's what sends the email. The key is to trace backward in the code to see where it gets the value for the exchange name from, and figure out why that's not working. It may help to set up a local run of the application and try to test some of the functions that
_exchange_from_queue is calling. You might also set up the testing environment for the application and find the test which exercises this code. There are some instructions in the README for both of those.
As with the last bug you worked on, I'm not terribly familiar with this code so my advice is what I would do in this situation -- I don't actually know the answers!