Akka cluster & DistributedPubSub on kubernetes Message goes to dead letters

We are using Akka cluster & DistributedPubSub on kubernetes,
We have a problem, in some cases when we are calling “mediator.ask” the target actor is not receiving the message and the message goes to dead letters.
It happens even if the target actor is on the same kubernetes pod as the sender.
Does anyone have an idea why it can happen?

Subscription is async, so you don’t know that a local subscription was completed and will receive messages until you have seen the DistributedPubSubMediator.SubscribeAck response. Did you see that before you published a message and did not see it arrive?

Note that for the distributed case there is an additional time period until the subscription has been gossiped to all nodes, the SubscribeAck only confirms the local subscription and not that it reached all nodes in the cluster.