The information returned from xdmp:host-get-ssl-fips-enabled is always computed on the host specified in the $host-id parameter, even if the call is evaluated on an App Server running on a different host. That is, when the API call is issued, MarkLogic Server communicates with the specified host for the boolean value whether fips mode is enabled in it and returns the boolean value from the perspective of the specified host (not from the perspective of the host in which the XQuery API is evaluated).