I think you need to concentrate on what really is the problem instead, since what you've narrowed down there is a fix for another bug that somehow hides the bug you're experiencing.
The bug being fixed there is that refs to the fd/shuffler objects no longer gets lost when an error is thrown through the backend. Without it you got leaked objects (presumably shuffler objects since WebServer isn't affected).
Are you sure the error isn't legitimate? Have you checked the threads involved? I'd start with finding out which thread the backend think is running it, and see what that thread really is doing.