When the cluster auto-repair and symmetry task does something, it's only written to console.log, not log.nsf. For the administrator, the activity should be easily accessible via log.nsf.
[010356:000002-00007FBE2E6F4740] Queued repair request for blabla.nsf
[010356:000002-00007FBE2E6F4740] REPAIR: 1 file(s) queued for repair
[008996:000060-00007F6B70F9F700] REPAIR: 08/08/2019 09:46:10 Job-00526.1 *Copying* - blabla.nsf from CN=Domino/O=ACME