Seems like pfSense or the service watchdog was confused by the install.
I kept getting mails , that service watchdog was starting the Zabbix agent , and it was not running if showing status --> services.
System log seemed to indicate that it was installed ok.
I went to the Services --> Zabbix Agent , and disabled the service
Waited 10 sec , and enabled the service
Problem gone , service is running
Maybe disable the service , before packet uninstall
And enable the service after installing the new version of the package
/Bingo