Following error I got,

Warning: Creating default object from empty value in /var/www/app_gic_wordpress_1/html/wp-content/plugins/wp-multi-network/wp-multi-network/includes/functions.php on line 238

Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 130968 bytes) in /var/www/app_gic_wordpress_1/html/wp-includes/class-wp-network.php on line 132

Further investigation in functions.php line number 234 overriding $current_site variable like below and this get_network( function pulling wrong data.

$current_site = get_network( $new_network );

Line 201 $current_site variable declaration as a global and overriding line number 234

global $wpdb, $switched_network, $switched_network_stack, $current_site;

If I command this line it's working properly
//$current_site = get_network( $new_network );