logging: heartbeat vs fwcm-heartbeatd, 500 Opcode Failed

Sophos Support today told me, they wanted but cannot enable fwcm-heartbeatd debug logging. The service is at status: UNREGISTERED

service fwcm-heartbeatd:debug -ds nosync

500 Opcode Failed

From https://docs.sophos.com/nsg/sophos-firewall/18.0/Help/en-us/webhelp/onlinehelp/nsg/sfos/concepts/LogFileDetails.html

fwcm-heartbeatd should be "Heartbeat to Sophos Central communication service". The log is empty/blank.

So is this service and logging not enabled as default in v18 MR5?

XG430_WP02_SFOS 18.0.5 MR-5-Build586# service -S |grep heartbeat
fwcm-heartbeatd      UNREGISTERED,DEBUG
heartbeat            RUNNING

All three fwcm- logfiles are empty and the services are UNREGISTERED.

XG430_WP02_SFOS 18.0.5 MR-5-Build586# service -S |grep fwcm
fwcm-updaterd        UNREGISTERED
fwcm-heartbeatd      UNREGISTERED,DEBUG
fwcm-eventd          UNREGISTERED

Our firewalls are registered in Central. Now support want's us to unregister, then reregister both appliances.

The register status currently shows:

XG430_WP02_SFOS 18.0.5 MR-5-Build586# central-register -status
This SFOS instance is currently registered with Sophos Central

  access_token        : c7xxxxxx
  device_uuid         : ed9xxxxxxx
  pic_uri             : utm-cloudstation-eu-central-1.prod.hydra.sophos.com
  refresh_token       : ALWxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx