Hello, I have the same problem too but it depends on the plugin. When I change set up of some, I get a 404 page. With other plugins, I’m redirected to the dashboard of the site with this url “…/network-blog-name/wp-admin/?c=1”.
I tried to modify the admin page of BP-share-it plugin where I changed action=”options.php” to action=”../options.php”. It worked but not for other plugins…