MT Help needed

I need some MovableType help with MT 3.15. Here’s my problem on another blog:

Using dynamic publishing and it’s been working well for quite some time; however, I’ve just recently run into a problem. If I post into a top level category as the primary category, the indivudual archive for that page isn’t created. If I the primary category is a subcategory, it works great – even if the top level category is an “additional category”. The entries show up in the index and category archive, they just aren’t available if you want to click on that entry.

Post to DOGS = 404 error for archive page
Post to DOGS>YELLOW = works great

If I build the 3000+ entries as static, it works great. Thoughts?