sodium lib: phpsessionclean.service displays a rogue WARNING on syslog

Description

As documented on manual "As of PHP 7.2.0 this extension is bundled with PHP. "

Consistent with this, extension on php.ini is commented...
;extension=sodium

...while php -i shows support

sodium

sodium support => enabled
libsodium headers version => 1.0.18
libsodium library version => 1.0.18

A bug -I guess- in the startup code is causing a warning to appear on syslog:

Jun 23 10:39:03 dev systemd[1]: Starting Clean php session files...
Jun 23 10:39:03 dev sessionclean[69737]: PHP Warning:  PHP Startup: Unable to load dynamic library 'sodium' (tried: /usr/lib/php/20210902/sodium (/usr/lib/php/20210902/sodium: cannot open shared object file: No such file or directory), /usr/lib/php/20210902/sodium.so (/usr/lib/php/20210902/sodium.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
Jun 23 10:39:03 dev systemd[1]: phpsessionclean.service: Deactivated successfull

PHP Version

8.1.2-1ubuntu2.11

Operating System

Ubuntu 22.04

Start by reproducing the warning from phpsessionclean.service on PHP 8.1.2 with sodium enabled in php -i and commented in php.ini. Compare the service's PHP configuration with the reported startup behavior; done means sodium support remains enabled without the rogue syslog warning.