The bulk user subscribe functionality only works on the admin user (i.e. The admin user is the only user affected by the bulk subscribe function.)
I initially thought this problem had been caused by the fact that I'd imported most of my users, but no, I've just replicated this behaviour on a completely fresh WordPress 3.3.2 installation (though, come to think about it, through my ISP's 'one-click install' process). Can anyone replicate it elsewhere?
Just for clarity, here's what I did in the Subscribers section of Settings:-
- Select 'All Registered Users (849)' from the drop down list
- Click Filter
- Scroll to bottom of page
- Select Subscribe radio button
- Select all [categories] checkbox
- Click Bulk Update Categories
After which, only one user (the admin user) appears in the drop down filter list under Registered Subscribers, all other users remain unsubscribed.
Thanks for your consideration,