[Eric V. Smith]
>  But the issue is 12 years old and doesn't cause any real problems 
> as far as I can see, so it's hard to get excited about it. 
> And as we've seen there are a lot of corner cases. I'd hate to 
> make things worse.

I ooncur with Eric and think this ought to be closed. It is a oddity but has proven itself to be harmless in the wild.  At this point in the life cycle of %-formatting it would be prudent to value stability over niggling behavior changes.