The included /etc/logrotate.d/syslog-ng file for syslog-ng (3.27.1-1.0) assumes that the system is running systemd. Any restarts after subsequent logrotation will
therefore fail, and the main system logging will cease.

This would probably be better handled with a post-install hook if a separate .nonsystemd package is not create which for instance would look like the following:

size 50000k

/var/log/messages.log /var/log/auth.log /var/log/mail.log /var/log/kernel.log /var/log/errors.log /var/log/daemon.log /var/log/user.log /var/log/syslog.log /var/log/acpid.log /var/log/crond.log /var/log/lpr.log /var/log/uucp.log /var/log/news.log /var/log/ppp.log /var/log/debug.log {
missingok
sharedscripts
postrotate
rc-service syslog-ng restart 2>/dev/null || true
endscript
}