I discovered this odd behavior of the 'host_deatils_ui' setting after migrating an existing foreman instance from 2.4.x -> 3.2.1.

[root@foreman ~]# /usr/sbin/foreman-rake -- config k 'host_details_ui' --unset
host_details_ui: true
[root@foreman ~]# /usr/sbin/foreman-rake - config k 'host_details_ui' -v false
ERROR: Invalid value false for host_details_ui - ["Value is not included in the list"]
[root@foreman ~]# /usr/sbin/foreman-rake - config k 'host_details_ui' -v '["false"]'
ERROR: Invalid value ["false"] for host_details_ui - ["Value is invalid: must be boolean"]
[root@foreman ~]# /usr/sbin/foreman-rake - config -k 'host_details_ui' -v '[false]'
ERROR: Invalid value [false] for host_details_ui - ["Value is invalid: must be boolean"]

<after changing the setting to false via www ui>

[root@foreman ~]# /usr/sbin/foreman-rake -- config -k 'host_details_ui' -v 'false'
host_details_ui: false