I found a solution, but I’m not sure it is the right one. I changed the following in the buddy press community stats > admin > bp-community-stats-admin.php file.
For the form post it was set to:
<form action=”<?php echo network_admin_url(‘/admin.php?page=bp-community-stats-settings’); ?>” name=”bp-community-stats-settings-form” id=”bp-community-stats-settings-form” method=”post”>
I changed it to:
<form action=”options-general.php?page=bp-community-stats-settings” name=”bp-community-stats-settings-form” id=”bp-community-stats-settings-form” method=”post”>
and everything works now. Looks like a bug to me?