Hi Shawn,
It is most likely going to be one of two things:
- The On-Page optimisation for the Category pages is not direct enough to rank for all product pages and therefore you would need to re-focus the on page optimization and messaging to the products you are directly aiming to rank for.
- You have built backlinks or internal links to the product pages so they hold more authority (you can check the PR and PA/DA of your pages vs. category pages for an idea)
Possible solutions are:
- Re-optimise the category pages to be relevant for the products you want to rank
- Build more powerful backlinks and authority to the category pages
- Make category pages canonical page for product pages (probably not the ideal solution but just a thought).
I guess the real question is why wouldn't you want clients seeing the exact product they are trying to search for? If they are searching XL Blue Widgets and you would prefer they go to the Widgets page, then it doesn't make too much sense?
Hope this offers some insight.