Validate that "Found healthy block" is really an error

We got a prometheus SLI alert which appears to be caused by an error message which doesn't sound like it's really an error: production#3211 (closed)

The logged msg is "msg": "Found healthy block", - This doesn't sound like something we should be alerting on. See production#3211 (comment 469619538)

Someone familiar with this error message should validate whether it is really a problem, and either remove it or make a note in the runbook with what to do about it.