When you view a category, you view it in the context of a sandbox. This means that you are viewing the category's settings as it exists as deployed, plus any undeployed changes made to the category in that sandbox.
If a category has changes in it in that sandbox, the category name will be yellow and there will be a pencil icon next to the category name, like this: ![]()
On a category's detail page, any fields that have been changed from the deployed version will be outlined in the color of the sandbox.