I have a WordPress 6.1 multisite with about 400 websites (every site have it’s own child theme), working ok since months. Today I go to wp-admin and got an error just after login (in apache error logs) :

[16-Mar-2023 11:18:23] WARNING: [pool foo.bar] child 895600 said into stderr: 
"PHP message: PHP Fatal error:  Allowed memory size of 1073741824 bytes exhausted 
(tried to allocate 60396269940 bytes) 
in /var/www/vhosts/foo.bar/httpdocs/wp-admin/includes/template.php on line 1268"

The problem appears only in the admin dashboard of the network and even of a single site ! The front is OK. The last installed plugin what a month ago, same thing for themes.

Why WP-admin needs so much memory ? Do I really need to add this in php.ini :

memory_limit = 6000M

6Gb of ram for WordPress ???? This is crazy …