Problem Summary: The timeout of a multigroup is based on the timeouts of the protection groups in the multigroup. If the timeout of a protection group has been changed but the configuration of a multigroup that contains the protection group has not been refreshed (through a validate command, for instance), then an attempt to set the timeout of the multigroup errors out based on the older timeout of the protection group as known to the multigroup. This situation happens when the new proposed multigroup timeout does not conform with the earlier known timeouts of the constituent protection groups.
Workaround: Refresh the configuration of the multigroup using the geomg validate command and then set the proposed timeout on the multigroup using the geomg set-prop command.