If this has indeed reverted, and it’s not because of any plugin or custom theme you may have installed, please report this as a bug on trac.buddypress.org.
This has been this way for some time now.
This topic should give you more info on this…
https://buddypress.org/forums/topic.php?id=1382#post-6727
If you login through the quick-login box in the header, you should always get redirected to whatever page you were on. If you click “Login” in the buddybar, it would need to save the referring page on the wp-login.php page load, which is more of a WPMU issue than a BuddyPress issue it sounds like.
I’m with Michael. If you’re logging into a member blog, you should always be redirected back to the root. Makes no sense.
If anyone is looking to hack the adminbar so that when users log in, they stay on the current blog they’re on, just edit the bp-core-adminbar.php file and change the reference to $bp->root_domain, under the “log in and sign up links” section, to $current_blog. Also, I took out the redirect as well. So, my login widget now looks like this:
// **** "Log In" and "Sign Up" links (Visible when not logged in) ********
function bp_adminbar_login_menu() {
global $bp;
if ( !is_user_logged_in() ) {
echo '<li class="bp-login no-arrow"><a href="' . $current_blog . '/wp-login.php">' . __( 'Log In', 'buddypress' ) . '</a></li>';
// Show "Sign Up" link if registrations are allowed
if ( get_site_option( 'registration' ) != 'none' ) {
echo '<li class="bp-signup no-arrow"><a href="' . bp_signup_page(false) . '">' . __( 'Sign Up', 'buddypress' ) . '</a></li>';
}
}
}
