Getting pq: there is no unique or exclusion constraint matching the ON CONFLICT after upgrade from 12.1.1 to 12.2.1

Did an upgrade from 12.1.1 to 12.2.1.

Rolling upgrade with two instances of 12.1.1 running.

After the new pod came up with 12.2.1 I see loads of occurrences of:

pq: there is no unique or exclusion constraint matching the ON CONFLICT specification

Failed to save alert rule state","org_id


Is this due to a migration job failing?
Should I stop Grafana completely and then start one instance at the time?

If the problem persist, how can it be resolved?