NoMoreElementsNeeded occurred in S3Stream.download

I’m researching some error occurred in our system using alpakka 3.0.3.

Our system composes of S3 source and DynamoDB sink. It was failed with SubscriptionWithCancelException.NoMoreElementsNeeded exception having null stack trace. We could not find out where it happened. We are using the following libraries:

  • akka v2.6.14
  • akka-http v10.2.4
  • alpakka v3.0.3
    • akka-stream-alpakka-csv
    • akka-stream-alpakka-s3
    • akka-stream-alpakka-dynamodb

We suspected cancel has been called somewhere. Our system fetches a S3 object by S3Stream.download method. The method eventually calls Http().singleRequest in S3Stream.singleRequest. It looks somehow, the method Http().singleRequest calls cancel without any cause.

I read this topic and change settings to the following:

akka.http {
  client {
    stream-cancellation-delay = 10000 millis
  }
}

but it did not work for us.

Does anyone know how it comes and how I can research it? or has the same issue?

Thank you.