PHP 7.3 FPM dies without a trace

PHP 7.3 FPM dies without a trace​

Plesk 17.8.11 Update35, Ubuntu 16.04 LTS, x64​

A couple of times per day, the fpm process for php 7.3 just dies, leaving all websites using PHP 7.3 down.
The watchdog does not detect any problems either.
There is no sign of the process dying in the fpm logs.​

Have a couple of...​