There are tons of events generated by the secondary SpectroSERVER (precedence 20) during the OnLineBackup that appear after the secondary SS is restarted.
Spectrum: Any version in Fault-Tolerant environrment
The issue is resolved by adding the following parameters in the $SPECROOT/SS/.vnmrc file of each secondary SpectroSERVER host:
is_secondary=TRUE
delete_sec_startup_events=true
Stop/start the secondary SpectroSERVER to put the change in place.
As per Engineering, this event from secondary is expected: