BuddyPress.org

Found the culprit. I had replaced this in the members-loop.php:

<?php if ( bp_has_site_members( 'type=active&per_page=10' ) ) : ?>

with this:

<?php if ( bp_has_site_members( 'type=random&per_page=10' ) ) : ?>

But WHY does that break the Ajax search?!

Or is ‘random’ not an accepted type? It did give the required result…