If you updated your environment to php 7.3 or higher, there is a good chance you will have default syslog settings that is syslog.filter set to no-ctrl
http://php.itronic.at/manual/en/errorfunc.configuration.php#ini.syslog…;
This will in turn cut of your messages on new lines and your syslog module will be sending broken logs
https://bugs.php.net/bug.php?id=77913 this is fixed here as https://github.com/php/php-src/pull/4265 so you can use "raw" format if you want and set your php as
ini_set("syslog.filter", "raw");
or just set it in your runtime config to that value.
https://www.php.net/manual/en/errorfunc.configuration.php