Please forgive me as I have overlooked this issue several times over the past few days simply because I had already flagged it as a Feature Request and moved it to our feature backlog. Because of this, I didn't check it again when you made a new post. Please be wary when posting bugs that you create a new issue for new bugs, or that the existing issue is at least categorized as a bug.
There haven't been much except feature requests for months, so we have directed our attention to our development site where we are working on the next major version, and only check in on the live site once or twice daily. To be honest we didn't expect so many bugs to pop up all of a sudden when there hasn't been a new release. My apologies in general for being slow in getting back to you.
While I can't speak for everyone else here, I just noticed myself that I had email monitoring turned off somehow. I have turned it on now, so I should start getting alerts again when users post new issues.
As for this one, I'll need to create a really deep multi-level book and get back to you. Based on what I know of how the TOC generation is written, I'm not sure if there will be an easy way to fix this. You might have to wait for a new patch on this one.