Steps to reproduce:

1. Upgrade to 4.4.8-1 on SLES 12
2. Will give RPM warning:

(22/22) Installing: zabbix-agent-4.4.8-1.el12.x86_64 ...................................[done]
Additional rpm output:
/var/tmp/rpm-tmp.CQLBOR: line 1: fg: no job control
warning: %post(zabbix-agent-4.4.8-1.el12.x86_64) scriptlet failed, exit status 1
/var/tmp/rpm-tmp.AeDB4F: line 1: fg: no job control
warning: %postun(zabbix-agent-4.4.7-1.el12.x86_64) scriptlet failed, exit status 1

1. Running rpm -q --scripts zabbix-agent shows:

   preinstall scriptlet (using /bin/sh):
   getent group zabbix > /dev/null || groupadd -r zabbix
   getent passwd zabbix > /dev/null || \
           useradd -r -g zabbix -d /var/lib/zabbix -s /sbin/nologin \
           -c "Zabbix Monitoring System" zabbix
   :
   postinstall scriptlet (using /bin/sh):
   %systemd_post zabbix-agent.service
   preuninstall scriptlet (using /bin/sh):
   if [ "$1" = 0 ]; then
   %systemd_preun zabbix-agent.service
   fi
   :
   postuninstall scriptlet (using /bin/sh):
   %systemd_postun_with_restart zabbix-agent.service
   ...

    

2. "%systemd_post", "%systemd_preun", "%systemd_postun_with_restart". These are RPM macros that are meant to be expanded when the RPM package is built. As to the reason for the error above, the RPM scriptlets are run through /bin/sh:

Result:
Errors on upgrade/install, service not being restarted as expected on upgrade.
Expected:
No warnings, post-install scriptlets should run

Fix:

Build machine needs packages built with BuildRequires: systemd-rpm-macros