Message was not delivered log entries in cassandra persistence plugin


I’m using Akka Persistence 2.6.10 with Cassandra persistence plugin 1.0.1
I noticed that my logs are full of the info messages of the following form:
“message”:“Message [java.lang.String] from Actor[akka://ActorSystemName/system/akka.persistence.cassandra.journal/tagWrites/PersistentActor#258709188] to Actor[akka://ActorSystemName/system/distributedPubSubMediator#755773826] was not delivered. [164] dead letters encountered. If this is not an expected behavior then Actor[akka://ActorSystemName/system/distributedPubSubMediator#755773826] may have terminated unexpectedly. This logging can be turned off or adjusted with configuration settings ‘akka.log-dead-letters’ and ‘akka.log-dead-letters-during-shutdown’.”

I’m wondering if this is something I should be worried about? If not, is there are some configuration parameter I can change to get rid of these messages?

Probably related to akka.persistence.cassandra.pubsub-notification (See in reference conf: being enabled but not working, could for example be caused by enabling in a non-clustered app.

Indeed, removing the read-side leads to this behavior. Thank you very much!