...does not so much go bad as become interminable. Defending Walls is enduring the wait for the galleys, which is unnerving at the best of times, while the research needed for the third book seems to be a self-seeding process. The more that is done, the more details are uncovered that need to be at least known if not covered in depth. It never ceases to astonish me how much work is needed to verify a throwaway comment by an extremely secondary character.
Fascinating though it all is, the slow speed of the process never fails to be somewhat alarming - two weeks researching produces less than 500 words at times.
(And then of course the Dread Editor will doubtlessly demand their removal, but I choose not to think about this.)
A happier thought is that the galleys and proofing and rechecking may - may - be in time for a Christmas release. Which would be an astounding thing all on its own...