I was having the same problem and just figured it out.
First: You need to set separate sidebars for the page and for the category. Doesn’t seem to work if you try to do both with one sidebar.
Second: The category name can’t have spaces in it. I spent hours trying to get it to work and when I renamed the category to use spaces instead of hyphens it finally started working. Not the best solution if your category names are displayed publicly, but at least it works…
