I'm currently posting this with TornTools enabled.
I'm resubmitting this as either a bug or faulty logic in the category display data: https://www.torn.com/forums.php#/p=threads&f=19&t=16474904&b=0&a=0
My bazaar, Medical Supplies, has only sold medical supplies for the past 14+ days. Many of the others in medical category list additional items outside of the medical supplies category presumably selling some. Either there's an error causing mine not to show up or the column of numbers in category specialization is misleading. The api says these are unique weekly buyers for both item specialization and the category specialization. I have at least 61 unique buyers in the medical category according to the item specialization and I haven't sold non medical items in the last week. If it's not a bug then the number displayed in the category specialization should display what's being measured.
Mentions: Bazaar Directory Categories Not Working as Implied