ISPconfig 3.2.9 not issueing LE certificates for websites when using PHP 8.1 (7.4 works)

Summary: see Subject

• Single server setup with Ubuntu 22.04, ISPconfig 3.2.9

The problem: I cannot get ISPconfig to issue a letsencrypt certificate (using acme.sh) for this website. This is the cron output if I click "SSL" and "LE SSL" in the website (vhost) or vhost subdomain settings:

Sat Dec 3 03:31:01 PM CET 2022 PHP Warning:  Undefined array key "CA_path" in /usr/local/ispconfig/server/plugins-available/apache2_plugin.inc.php on line 269
Sat Dec 3 03:31:01 PM CET 2022 PHP Deprecated:  stristr(): Passing null to parameter #1 ($haystack) of type string is deprecated in /usr/local/ispconfig/server/plugins-available/apache2_plugin.inc.php on line 1172
Sat Dec 3 03:31:01 PM CET 2022 PHP Deprecated:  trim(): Passing null to parameter #1 ($string) of type string is deprecated in /usr/local/ispconfig/server/plugins-available/apache2_plugin.inc.php on line 1197
Sat Dec 3 03:31:01 PM CET 2022 PHP Warning:  Undefined array key "csr" in /usr/local/ispconfig/server/plugins-available/apache2_plugin.inc.php on line 1286
Sat Dec 3 03:31:01 PM CET 2022 PHP Warning:  Undefined array key "website_autoalias" in /usr/local/ispconfig/server/plugins-available/apache2_plugin.inc.php on line 1404
Sat Dec 3 03:31:01 PM CET 2022 PHP Warning:  Undefined array key "vhost_proxy_protocol_enabled" in /usr/local/ispconfig/server/plugins-available/apache2_plugin.inc.php on line 1795
Sat Dec 3 03:31:01 PM CET 2022 PHP Deprecated:  trim(): Passing null to parameter #1 ($string) of type string is deprecated in /usr/local/ispconfig/server/plugins-available/apache2_plugin.inc.php on line 1945
Sat Dec 3 03:31:02 PM CET 2022 finished server.php.

It seems to me that ISPconfig is trying to create a "real" SSL certificate, not an ACME one.

Correct behaviour

LE certificates should be assigned

Environment

Ubuntu 22.04, ISPc 3.2.9