URE protects users with ‘administrator’ role from each other under WP multisite by deafault.
In order to show single site administrators back, and allow edit users:
1) Go to Network admin->Settings->User Role Editor->Multisite and turn ON the “Allow single site administrator access to User Role Editor” and “Allow non super administrators to create, edit, and delete users”.
2) Go to “Users->User Role Editor” and grant to ‘Administrator’ role the ‘ure_manage_options’ user capability.
Another way is switch URE built-in administrators protection using ‘ure_supress_administrators_protection’ custom filter. Just return TRUE for it.