One thing I've noticed is that if I enable the Can send new PMs to staff members? option, I get the restriction message when composing a new PM regardless of whether the group is actually restricted or not. It doesn't actually block a non-restricted group from sending the PM, but the warning really shouldn't be there for those groups.
The links for Sign in and Register on hidden posts are wrong for me. It is not removing the topic title from the link, only adding index.php after, so the resulting link just displays the topic page again.