Muting isn’t a restriction. Because you must use everyone to show content to randoms and Google, then every your users have access to all those categories, mute or not, and they’ll see right search results.
If you really are using group restrictions, and at same time keeping non-logged visitors and Google out from those restricted categories, then there is a bug. But I doubt that because it works here (and on my forum).
So my bet is you are using everyone for reading.