Not to my knowledge, but perhaps a much better UX question is, "WHY are there no/few traditional UX discussion forums?"
In the evolving web, traditional, threaded discussion forums are becoming a thing of the past. Why? Traditional forums are usually built around legacy principles. They tend to lack or aren't built around these features/ideas which today's web demands:
- Article tagging instead of categorization/filing
- User contribution, feedback, and interactivity
- Some form of social networking/profiling (they can become "cliquey")
- Scalability and user or 'intelligent' customization
I always used to add forums to the sites I built... but that was years ago. I see this less and less now.
Anyway, on Stack Exchange sites I find what I am interested in, good at, etc, much quicker than I do on any traditional forum. So I know I haven't directed you to a good, active, UX forum, but at least now you can know why.