That depends on the user’s preference for
Notify me about topics in categories or tags I’m watching that also belong to one I have muted
It’s a little hidden, but you can see it when you are watching at least one category and mute at least one tag:
Then you can change it, save and adjust your tracking preferences again.
Admins can also configure a default for it in the site settings.
What I often forget while testing is that the tracking levels of existing topics are often no longer based on the category/tag default, but are influenced by auto tracking based on reading and replying.