pfSense » pfSense Packages

i have had this on both pfSense + 26.03.1 and pfSense 2.8.1

Install particular packages, in my case "Netgate Coreboot Upgrade" and "Zeek". Deinstall them. Then backup the configuration.
when you restore the configuration you get remnants of the original install;

ie the pfSense + 26.03.1 System menu has "Netgate Coreboot Upgrade" even though it isnt there

in the case of zeek on 2.8.1 you have a service status/zeek that never starts.

if you reinstall those packages, then deinstall it fixes the issue. In the case of Coreboot Upgrade that cant be done since the package no longer exits and was replaced by Netgate Firmware Upgrade, and has a different name.

Likely deinstalling the package doesnt remove everything, and the restore function gets confused and think its there, even though it isnt.