Today I went to my profile on Open Source beta and clicked on "track a tag badge instead" option in the leftmost frame. Since this moment, the section doesn't show any controls whatsoever:
I observed the same behavior on another beta site (Arduino). On all sites which are not in beta tracking for tag badges seems to work fine. I suppose I should report it here instead of doing so on every beta site.
Edit: there is a related question where the OP didn't have any tags to track before he clicked, which is not my case. Also, that question has no answers.